Add text, images and marks to a PDF

What this editor can and cannot do

The editor shows each page as a preview and lets you put new objects on top of it: text boxes, images, freehand strokes, highlights, rectangles, ellipses, lines, arrows, white boxes and checkmark or cross stamps. Every object can be moved, resized or deleted, undo and redo are available, and you can work across all pages of the document. When you save, the objects are written into a new PDF and your original file is left as it was.

The important limit is that it cannot edit the text that already exists in the PDF. A PDF does not keep text as a flowing paragraph you can click into; it keeps positioned characters, often with fonts that are not embedded in full. Real in-place editing needs a layout engine that this browser tool does not include, so what you see in the original stays in the file underneath anything you add.

That still covers a lot of everyday work: filling in a flat form that has no fields, adding a note or a date, marking up a drawing, hiding an outdated figure and writing the new one next to it, or adding a stamp before sending a file on.

Why existing PDF text cannot be edited in place

A word processor stores a document as paragraphs that reflow when you type. A PDF is closer to a printed page: each line is a set of characters placed at fixed coordinates, frequently split into fragments, with fonts embedded only for the letters the document uses. If you deleted a word, nothing would tell the file how to close the gap, and if you typed a letter that the embedded font lacks, it could not be drawn.

Programs that advertise full editing usually convert the page to a word-processing layout in the background, guess where paragraphs are, and export again. That guess frequently breaks columns, fonts and spacing. This tool takes the honest route instead: it leaves the original alone and lets you add objects on top.

Changing text: the cover-and-retype method

When a word or number has to change, use two objects together. First draw a white box over the old text with the cover tool, sized a little larger than the text and matching the page colour. Then add a text box on top of it, and choose a font, size and colour that resemble the surrounding text.

Keep the limits of this method in mind. The original words are hidden, not deleted, so anyone can still copy them from the saved file. That matters for anything confidential such as an account number or a salary. In those cases use Redact PDF, which re-renders the page so the covered content is genuinely gone.

• Zoom in before placing the box so it fully covers descenders and punctuation.
• Match the font size to the neighbouring text; a slightly smaller size usually looks more natural than a larger one.
• On coloured or patterned backgrounds a white box will show, so pick the page colour or use a different approach.

Better routes when you need real text editing

If you have the source document, change it there and export a new PDF. If you only have the PDF, PDF to Word rebuilds an editable .docx from its text; you edit that file and turn it back into a PDF with Word to PDF. Expect to correct the layout, particularly with columns, tables and unusual fonts.

For a page that is only a scan, run OCR PDF first if you want selectable text, and keep in mind that editing still means covering and retyping. To add page numbers, headers or a watermark across the whole file, the dedicated Add Page Numbers and Watermark PDF tools are quicker than placing the same object on every page.