Cover versus permanent
Cover only paints black boxes. The words can still be copied, searched, or extracted. Permanent mode rebuilds each page that has a box as an image, so the covered text and images are not in the new file. Pages without boxes keep their text.
Metadata, bookmarks, and attachments are dropped from the redacted copy. Text on a permanently redacted page is no longer selectable.
How to check
Draw a box over each name, account number, or image. You can scan selectable text for emails, phone numbers, Social Security numbers, and card numbers, then draw the boxes yourself.
After you download, MyPDF searches the new file for the words that were inside the boxes. If they are gone, the page says so. If you used cover only, it says the text is still in the file.
What this is not
This is a practical redaction for a contract, statement, or form you are about to send. It is not a certified legal product. If a law or a contract requires a specific redaction certificate, use a product that provides one, and still read the result yourself.
The file never leaves your browser. One job is counted when you download.
Questions
Is a black box enough?
No. Cover only leaves the text in the file. Use Permanent mode when the words must be gone.
Does redaction upload the PDF?
No. Drawing, removal, and the search of the result all happen on this device.