Black it out.
For real this time.

1. 1Open the PDF with the secrets in it.
2. 2Drag boxes over what has to go, or use Find & redact to find every e-mail address, IBAN or name at once.
3. 3Click Download. Those pages are rebuilt without the text underneath, so nothing can be copied back out.

No PDF handy? Try a very official sample form

No upload bar, because nothing gets uploaded.