Whiteout a PDF

A white rectangle is drawn over the area, in the way correction fluid covers ink on paper. And exactly as with correction fluid held up to the light, what is underneath has not gone: the text remains in the file and can be selected, copied or recovered by anyone. This tool is for tidying a page, not for hiding anything. If information needs to be gone, use Redact, which removes it.

Is this the same as redaction?

No, and the difference matters. Whiteout covers; redaction removes. The covered text is still in the file.

When should I use it?

Tidying a scan, covering a stray mark, blanking a field you will print over.

How do I actually remove something?

Use Redact. It converts the affected pages so nothing remains underneath.