Edit PDF

Most free PDF tools let you add things on top of a page, but not change what is already written. Here every piece of text on the page becomes clickable: move the pointer over the page and the editable text is outlined. Click a line, a word in a table cell or a heading, and its words appear in the Text box above the page, ready to change.

When you save, the editor takes the old words out of the page and writes the new ones in their place, at the same position and size, in the closest standard font: sans serif for fonts like Arial or Helvetica, serif for fonts like Times, and monospace for typewriter fonts. The colour of the text is kept, so a blue link stays blue and a grey footnote stays grey. Because the old words are really replaced, a person who copies the text or searches the saved PDF finds your corrected version.

Choose Add text and click anywhere on a page to place new text: a note in the margin, a missing line in a form, a reference number or a date. Type it in the Text box; pressing Enter starts a new line. Choose the font, the size, bold or italic and the colour, then drag the text into place.

Add image puts a picture on the current page: your company logo on a letter, a scanned signature at the bottom of a contract, a photo in a document or a stamp on a delivery note. It appears in the middle of the page at a sensible size; drag it and resize it with the corner handle, and it keeps its proportions. PNG images keep their transparent background.

White out covers an area with a solid colour, white by default, just like correction fluid on paper. Use it to hide an old phone number, a mistake in a scanned page or a field that should stay empty.

A PDF is not a word processor file: each line of text is placed at an exact position, often in a font that is only partly stored in the file. That is why changing a PDF is harder than changing a document, and why many editors produce misplaced or garbled text.

This editor works line by line and checks its own work. After saving, it reads every page it changed again and compares the result with what you asked for: the lines you edited must show your new words, and every other line must be exactly as it was. If a page does not pass this check, for example because its text is stored in an unusual way, the editor saves that page with the old line covered in the page's own background colour and your new text on top. The page looks the same either way, and the download message tells you if any edit was covered rather than replaced.

New and changed text is written with the standard PDF fonts, which cover English and the other Western European languages. Characters they cannot show, such as Hindi, Arabic, Chinese or emoji, are replaced by a question mark, and the download message lists them. The original font of a document is not reused, because most PDFs only contain the letters they already use.

Scanned pages are pictures of paper: they have no text to click. Use White out and Add text on them, or first make the text readable with the PDF OCR tool. To hide sensitive information so that it can never be recovered, use Redact PDF, which removes it permanently. To fill in an existing form, Fill PDF Form is the quicker choice.