Edit PDF Online - Add Text, Draw, Highlight and Correct Words

Edit a PDF online without installing an editor

PDFs are designed to look the same everywhere, which makes them awkward to change. Yet the small jobs keep arriving: a date to fix on an invoice, a line to add to a form that is not fillable, a paragraph to highlight before a meeting, a logo to drop onto a certificate, an old phone number to wipe out. This free PDF editor handles those in the browser. You open the document, work on the page itself, and save a new copy.

It covers the jobs people search for as add text to pdf, write on pdf, annotate pdf and highlight pdf online, plus correcting a word that is already on the page. It does not rebuild a document the way a word processor does, and the sections below are specific about where that line falls.

How to edit a PDF, step by step

1. 1
   Drop a PDF onto the upload area, or click it to choose a file. The editor opens with page 1 on screen and arrows at the bottom to move between pages.
2. 2
   Pick a tool from the toolbar: Select, Edit text, Erase, Text, Draw, Highlight, Rectangle, Ellipse, Line or Image.
3. 3
   Choose a colour from the eight swatches or the Custom colour picker. Adjust the Font, Bold, Italic, Text size or Thickness that appear for the tool you picked.
4. 4
   Click or drag on the page. To type new words use Text and click where they should begin. To change a word already there, double-click it, edit it in the box that opens and press Enter or Apply.
5. 5
   Click an item with Select to move it, resize it from its orange corner, or change it from the strip above the page. Arrow keys nudge it one point, or ten with Shift held. Undo, Redo and Delete selected are the three icons on the toolbar.
6. 6
   Use the page arrows at the bottom to move through the document, then press Save PDF. The new file is downloaded with -edited added to its name.

What each tool does

• Select picks up anything you added, to move, restyle or delete it.
• Edit text opens the word you click on, already set in that spot's font size, weight and colour.
• Erase wipes a rectangle you drag in the page's own background colour.
• Text puts new words anywhere, in Helvetica, Times or Courier, with bold, italic, underline and an optional link.
• Draw is freehand, for circling or underlining by hand. Line and the shape tools make straight lines, Rectangle and Ellipse, outlined or, with Fill ticked, solid.
• Highlight lays a translucent coloured box over text, at 35 per cent opacity, so the words underneath stay readable.
• Image places a PNG or JPG picture. It lands at most about 220 points wide and is selected, so you can drag or resize it straight away.

How editing really works inside a PDF

The page is drawn by pdf.js, and everything you add sits on a canvas over it. Your edits are stored in PDF coordinates, with the origin at the bottom-left corner of the page, so zooming or resizing the window never moves anything. When you press Save PDF, the pdf-lib library writes each item into the document as real PDF drawing content: text objects, rectangles, lines and images. Nothing is flattened into a picture and the original page content stays as it was.

Existing words cannot be rewritten where they sit. In a PDF, letters are placed one by one from a font that often contains only the characters already used. So Edit text does what every browser-based editor does. It reads the paper colour around the word from the rendered page, covers the old word with a patch of that colour, and draws the new word on top, matching the original size, weight, slant and ink colour where it can. The patch matches shaded table cells and coloured letterheads, not just white paper.

Worked example: correcting an amount on an invoice

Say a typed invoice shows Rs. 4,500 in 12-point Helvetica and it should read Rs. 45,000. You double-click the amount, replace the text and press Enter. In Helvetica at 12 points the old words are about 50.5 points wide and the new ones about 57.1 points. The editor makes the cover patch at least as wide as the wider of the two, plus a small allowance, roughly 64 points once the extra point on each side is counted, and 12.96 points tall (1.08 times the text height). It starts 3.6 points below the text baseline and rises 9.36 points above it, which is enough for capitals and for a descender.

On screen, an A4 page of 595.28 points is drawn 900 pixels wide, so one point is about 1.51 pixels. If the new amount sits two points too high, tapping the Down arrow twice moves it 3 pixels, which is the precision you need to land on the old baseline. Shift with an arrow moves ten points, about 15 pixels, for coarse moves.

Characters the editor cannot draw

Text you add uses the three standard PDF font families, Helvetica, Times and Courier. These cover the Latin alphabet and common Western punctuation, not every script. Typographic quotes and dashes are quietly replaced with plain ones, the rupee sign is written as Rs., and a bullet becomes a hyphen. Anything the fonts cannot represent at all, which includes Devanagari and other non-Latin scripts, is left out.

You are told when this happens. A small warning appears under the typing box naming the characters, and after saving the status line lists the ones that were dropped. Do not expect to type Hindi onto a page with this editor. If a Hindi document needs a correction, edit the source file and export again, or use the document's own application.

Links, tints and other small controls

• Links: the box that opens when you edit a word has a link field. Type an address such as jobsixo.com and that word becomes clickable in the saved file; plain domains get https:// added and email addresses become mailto: links.
• Existing links: if the word you click is already linked, its current address appears in the box so you can change it or empty it to remove the link.
• Whole line: when you double-click, you get one word. The Whole line button widens the selection to the entire line.
• Cover: for Edit text and Erase, choose Match the page or Choose a colour to set the patch yourself.
• Page tint: None, Warm, Green, Blue, Pink or Grey lays a faint wash (12 per cent) over every page. Use it sparingly; it changes the whole document.
• History: undo and redo keep the last 40 steps.

Good uses for a quick PDF edit

• Fixing a typo, date or amount on a document whose source file you no longer have.
• Filling a flat form that has no clickable fields, by typing into the blanks. For documents that do have fields, fill the form fields directly.
• Marking up a report for review with highlights, boxes and short comments.
• Adding a logo or a stamp image to a certificate or letterhead.
• Blanking out an old address, a stamp or a price before sharing a file.
• Writing a short note beside a paragraph on a contract draft.

When another tool is the better choice

Covering is not deleting. When you erase or replace a word, the page still contains the old text beneath the patch, and the saved file keeps it selectable and copyable. If the point is to hide a phone number, an account number or a name for good, use true redaction, which destroys the text under the box instead of painting over it.

For a signature, sign the PDF with a drawn, typed or uploaded one. For a repeating mark on every page, stamp a watermark or number the pages rather than placing each item by hand. To remove, reorder or crop whole pages, rearrange the pages first, then come back here. If you need to rework a document heavily, convert to Word, edit there and export again.

Tips for clean results

• Double-click rather than drawing your own box when you change existing words. The match to size, font and colour is automatic.
• Keep replacement words about the same length as the old ones; a longer word widens the patch and may cross a nearby border.
• Zoom your browser to a comfortable level before you start, so small nudges are easy to judge.
• The editor opens files up to 100 MB and 100 pages, because every page is held in memory as a picture. For long documents, edit only the pages you need and keep a copy of the original. Every save writes a new file with -edited in the name.
• Open the saved file in a different viewer to confirm the result before you send it.
• Watch the edit count in the footer, for example 3 edits. It tells you how many items will be written into the file when you save.

Mistakes to avoid

• Treating Erase as secure. The old content is still in the file.
• Expecting scanned pages to be editable. A scan has no words to click on, and the editor says so. Use Erase to clear the area, then Text to type over it.
• Typing characters outside the standard fonts and not reading the warning.
• Highlighting with a dark colour. Highlight is translucent, but a very dark choice still makes text hard to read.
• Closing the tab before pressing Save PDF. Nothing is stored, so unsaved edits are lost when the page closes.

Limits and privacy

• The editor works on PDFs only. A password-protected file must be opened first, and the page asks you to remove the password.
• There is no OCR, text reflow, page insertion, table editing or form-field editing. Edits are placed objects, not changes to the document's structure.
• The whole document is read and every page is drawn when you open it, so a very long file takes a while to appear. Split big files first.
• Fonts are limited to the three families, each with bold and italic.
• Everything happens in your browser. The PDF is not uploaded, there is no account, and the saved file has no watermark.