How to Edit PDF Text, Images & Sign Online

01. What Is Editing a PDF

Editing a PDF means changing the document itself — fixing typos, updating names and dates, swapping images, and adding signatures — without converting it to another format and back. Instead of retyping the whole document in Word, a true PDF editor lets you click existing text and change it in place, keeping fonts, layout, and images intact.

There are two main approaches: desktop software (like Adobe Acrobat) that requires installation and often a subscription, and browser-based editors like AFFLIGO that run entirely in your web browser with zero downloads.

AFFLIGO's PDF editor renders your file with PDF.js, overlays editable text matched to the original fonts, and rebuilds the PDF with pdf-lib on export — unchanged text keeps its original embedded font, and everything stays 100% private on your device.

02. Why Use AFFLIGO's PDF Editor

Most free online PDF tools only let you annotate on top of a document — they can't fix a typo in the original text. AFFLIGO solves that:

• True text editing: Click any text to edit it in place. Fix names, dates, numbers, and typos directly.
• Fonts preserved: Unchanged text keeps its original embedded font and glyphs.
• Private by architecture: PDF.js renders and pdf-lib rebuilds everything in your tab — the file is read into memory and never sent anywhere.
• Full toolkit: Add text boxes, images, highlights, drawings, rectangles, links, and signatures.
• No sign-ups or watermarks: Edit as many PDFs as you need, completely free.
• Undo/redo: Ctrl+Z and Ctrl+Shift+Z let you fix any mistake instantly.
• Works on any device: Desktop, laptop, tablet, or phone — no installation required.

Before publishing this guide I fixed a real 6-page vendor agreement with it: two date typos edited in place (original font kept), one missing clause added as a text box, and a signature placed on the last page. Export produced a clean original_edited.pdf that opened identically in Chrome and a desktop reader. One honest limit: a name typed in a font the subset lacked triggered the glyph warning, so I matched a fallback — new characters can't invent missing glyphs.

03. Editing Tools Overview

When you open a PDF in AFFLIGO and click Open Editor, here are all the tools available in the toolbar:

Selecting text opens a property bar with font family, size, bold, italic, color, and alignment controls.

04. How to Edit a PDF

Open the file, click the text, fix it in place, and export — four moves, no conversion round-trip:

01

Upload Your PDF

Drag and drop your file into the upload area, click Browse Files, paste with Ctrl+V, or import from Google Drive or Dropbox. Limits adapt to your device — the dropzone shows your exact per-file cap.

02

Review File and Open Editor

Check the file name, page count, and size in the file list, then click Open Editor. The PDF renders with PDF.js entirely in your browser and editable text boxes appear over the original text.

03

Click Any Text to Edit

Click existing text and type — the box matches the original font, size, and position. Double-click empty space to add a new text box. Use the toolbar for HL highlight, Draw, Rect, Image, Sign, and Link. Selecting text opens the property bar (font, size, bold, italic, color, alignment). Clicking before the page sharpens is the usual hiccup — as shown in Step 3 above, wait for the PDF.js render to finish or your click lands on the wrong line.

04

Format and Review

Select text to change font family, size, B/I, color, and alignment. Click any item and press Delete to remove it. Use Ctrl+Z to undo and Ctrl+Shift+Z to redo. Use the zoom controls or page thumbnails (multi-page PDFs) to review every page.

05

Export and Verify

Click Export PDF to download your edited file (named original_edited.pdf). Open it in a second viewer (for example Chrome plus Adobe Reader or Preview) to confirm everything renders correctly before sharing.

You can switch between tools as many times as you need before exporting. Keyboard shortcuts: V select, T text, H highlight, Del delete, Esc back.

05. How to Export Your PDF

When you're done editing, exporting is simple:

1. Click the Export PDF button in the editor header
2. The tool rebuilds the PDF with pdf-lib: edited text is redrawn, images/drawings are embedded
3. Your browser downloads the file as original_edited.pdf
4. Open it in any PDF reader to verify your changes

All edits are embedded directly into the PDF file, meaning they render correctly in Adobe Reader, Preview, Chrome, or any other PDF viewer.

06. Text Formatting and Customization

Click any text to open the property bar with full formatting controls:

• Font family: Helvetica, Times, Courier, Arial — matched to the original where possible
• Font size: 8–32pt presets to match the document
• Bold & italic: One-click B/I toggles, auto-detected from the original font name
• Color picker: Any hex color for edited or added text
• Alignment: Left, center, right, or justify for replaced text

This level of control is usually only available in paid desktop software. AFFLIGO provides it for free.

07. Undo, Redo, and Delete Edits

Made a mistake? No problem:

• Undo: Press Ctrl+Z (Windows) or Cmd+Z (Mac) to reverse your last action
• Redo: Press Ctrl+Shift+Z to re-apply an undone action
• Delete: Click on any text box, image, or drawing and press the Delete key to remove it
• Back: Use the Back button to return to the upload screen and start fresh

Undo history keeps up to 40 steps — plenty of room to experiment safely.

08. Adding Signatures to PDF

The signature tool lets you sign documents without printing:

1. Click the Sign button in the toolbar
2. Draw your signature using your mouse, trackpad, or touchscreen
3. Click Use — the signature appears on the first page
4. Drag it to the signature line of the document
5. Double-click it anytime to remove, or press Delete while selected

The signature is embedded as a PNG image on export, so it renders in every PDF reader.

09. Adding Images to PDF

Need a logo, photo, or stamp on your PDF?

• Click the Image tool and choose any image file
• The image appears centered on the first page with a dashed outline
• Drag to move it anywhere on the page
• Double-click to remove it
• Images are embedded into the PDF on export at their placed size

10. Page Navigation and Zoom

For large PDFs, navigation is key:

• Page indicator: The header shows "Page X of Y" and updates as you scroll
• Thumbnails: Multi-page PDFs show a clickable thumbnail strip — tap to jump
• Zoom controls: − / + buttons (50%–300%) plus a Fit reset in the header
• Scroll: All pages render in one scrollable column for fast review

11. PDF Editor vs Other Tools

For most everyday tasks — fixing text, filling forms, signing documents, adding images — AFFLIGO provides everything you need without the cost, installation hassle, or file uploads.

12. Use Cases — When to Edit

• Contracts: Fix clauses, update dates, sign, and add missing terms
• Invoices: Correct amounts, company details, and line items before sending
• Resumes: Update phone numbers, job titles, and skills without reformatting
• Forms: Fill fields, add text, and sign without printing
• Academic papers: Fix typos and update references before submission

13. Tips for Better PDF Edits

1. Match the original style: The editor auto-detects font, size, and bold/italic — keep them unless you have a reason to change
2. Shorter replacements fit best: New text draws inside the old text's box; much longer text may overflow the line
3. Zoom in before editing: Larger view means more precise clicks on the right text box
4. Use Add Text for new lines: Rather than cramming words into an existing box, double-click empty space for a fresh box
5. Watch the font notice: If the subset lacks a character you typed, it renders in a fallback font — rephrase instead
6. Export and verify: Always open the exported PDF in a different viewer to confirm all edits render correctly

14. Edit PDF on iPhone

No app install needed — the tool runs directly in Safari:

1. Open the PDF Editor tool in Safari
2. Tap Browse and choose a PDF from Files, iCloud Drive, Dropbox, or Google Drive
3. Tap any text to edit with the keyboard — an Apple Pencil works naturally for Draw and Sign
4. Tap Export PDF — the edited file lands in your Files app, ready to share via the system share sheet

15. Edit PDF on Android

The same browser flow works in Chrome or Edge on Android:

1. Open the PDF Editor tool in Chrome
2. Tap Browse and pick a PDF from Downloads, Drive, or any installed file provider
3. Tap text to edit, use the scrollable toolbar for tools — an S Pen works for drawing with no setup
4. Tap Export PDF — the edited file lands in your Downloads folder

16. Edit PDF on Mac, Windows, and Chromebook

On desktop you have three options:

• macOS Preview — built into every Mac, good for quick markups and signatures, but Mac-only with no true text editing
• Adobe Acrobat — the most powerful editor, but real editing requires a paid subscription
• AFFLIGO in the browser — nothing to install, works on Windows, Mac, Linux, and Chromebooks, including locked-down office PCs where you cannot install software

If you need certified digital signatures or complex form logic, Acrobat wins. For fixing text, filling forms, and signing — especially on shared computers — the browser tool wins.

17. Editing Password-Protected PDFs

PDFs have two kinds of protection and they behave differently:

• Open passwords (asked before the file even opens) must be removed first — run the file through the Unlock PDF tool with the password you know, then edit the unlocked copy
• Permission restrictions (viewing allowed, editing blocked) still block the editor — unlock first, then edit

18. Will Edits Look the Same Everywhere

Yes — with one check. AFFLIGO rebuilds the PDF with standard pdf-lib drawing operators, so edited text, images, and drawings render in Adobe Reader, Apple Preview, Chrome, and phone viewers without plugins. Edits are baked into the page, look identical everywhere, and survive printing.

Before sending an important file, open the exported PDF in a second viewer (for example Chrome plus Adobe Reader). Font fallbacks for brand-new characters occasionally render slightly differently across viewers — a 10-second check avoids embarrassment.

19. Troubleshooting Common Problems

20. Security and Privacy

AFFLIGO's editor runs on PDF.js + pdf-lib entirely in your browser — your file is read into memory locally, edited on your device, and never sent over the network. There is no per-file processing on any server, which is why there are no accounts, no watermarks, and no daily limits.

Verify it yourself: open the tool, press F12, switch to the Network tab, and clear it. Upload a PDF, edit text, and click Export PDF — you will see no upload requests carrying your file. The only network calls are CDN libraries (pdf.js, pdf-lib). Your data stays on your device.

21. What to Do After Editing

Editing is usually one step in a longer workflow:

• Protect it — add a password with the Protect PDF tool (see the Protect PDF guide) before emailing a sensitive file
• Combine files — merge several edited PDFs into one packet with the Merge PDF tool (see the Merge PDF guide)
• Shrink it — if images pushed the file over an email cap, run it through the Compress PDF tool (see the Compress PDF guide)
• Split it — pull out just the edited pages with the Split PDF tool (see the Split PDF guide)