Edit & annotate
Underline Text
Underline selected passages.
How it works
- 1Upload your file — drag it in or pick it from your device.
- 2Choose the options you need; defaults work for most files.
- 3Press Process and watch the progress in real time.
- 4Download the result. Anonymous files are deleted shortly after.
What this tool does
- Accepts: .pdf · one file at a time
- Produces: pdf
- Runs on: the pdf worker, in an isolated process with a 3-minute ceiling
- Account: required, because the result is stored in your workspace
- API: available as
toolSlug: "underline-pdf"
Questions
Is this an annotation or a change to the text?
An annotation. The underlying text is untouched and the underline can be removed later.
Can I underline and highlight the same passage?
Yes, annotations stack independently.
Security note
Files are checked to be what they claim (by content, not extension), processed in a sandboxed worker with no network, and deleted on the schedule your plan sets. We do not run antivirus and do not claim to — please do not upload files you do not trust. Read the security page.