Edit text in a PDF

Yes, wherever that font has every character of the new text: the line is written in the same font, at the same size, colour and place, and the rest of the page stays as it was. Text beside it drawn another way (in another font, size, colour, opacity or spacing) or kept apart by the PDF (in a tag or a layer of its own) is a line of its own, with its own box, and stays as it was. A PDF usually carries only the characters it uses (a subset of each font), so a character a line never had is often missing from its font. The page then names the missing characters, and you choose Liberation Sans, Liberation Serif or Liberation Mono (regular or bold) or Noto Sans CJK for that line, which then looks different from the text around it; the preview shows it before you save.

No. Each line is changed where it stands: a longer line runs on to the right over what follows it on its line, a shorter one leaves a gap, and the lines below stay where they are. The list of changes and the result say which changed lines are wider than before.

Lines in a Type 3 font (glyphs the PDF draws itself), text written top to bottom or right to left (Arabic, Hebrew), text in an encoding this tool cannot write back, text whose font does not say which characters all its codes are, text in a font the page's graphics state sets (an ExtGState) rather than the text itself, text whose replacement text (ActualText, which a reader takes instead of the glyphs) also covers other text or a drawing, or is held in the PDF's tags, invisible text such as a scan's recognised text, and text inside a part of the page the PDF draws from one place (a form XObject, such as a header, a logo or a stamp) are shown with a dashed box: choose one to see why. Text in an annotation, and words that are part of a picture, such as a scanned page, have no box (OCR PDF recognises the words of a scan). An encrypted PDF has to have its encryption removed first, with PDF password.

You can change its text, but the copy no longer matches its signature, so a PDF reader shows the signature as broken. The page says so before you save, and your original file stays as it is.

On a page you changed, the old text of the line is replaced in the page's own content, and so is its replacement text (ActualText) where it has one of its own, so the copy holds only the new text there. Everything else in the file is as it was.

No. The page loads a PDF engine into your browser and every operation runs on your device. You can check this yourself in the browser's network panel: after the page has loaded there are no upload requests. Closing the tab discards the file.

No. These basic tools are free, have no page or file limits set by us, and never add a watermark. The practical limit is your device's memory.

Encrypted PDFs cannot be processed here. Remove the password first, then use this tool.

Nothing you open or type. While the tab is open, the tool pages keep a short list of the steps taken in it, in the tab's session storage: the step (page opened, started, succeeded, first success, used again or failed), the tool's name, the time, how many files were used and, for a failure, an error code; never a file name, the contents of a file or your text. It holds at most the latest 200 steps, and the browser deletes it when the tab closes. The page never sends it. Where a Report a problem button is shown, you can attach the last 20 steps to your report; nothing is attached unless you tick that box. In local storage the page keeps only choices you made: a Light or Dark theme until you choose System again, the language you picked with the EN / 中文 switch if it differs from your browser's language, and this tool in your recently used list if you switched that list on at the tools page.