Step-by-step: unlock a PDF you have the password for, the difference between user and owner passwords, and what to do when you've genuinely forgotten yours.
PDFs can have a 'user' password (required to open the file) and an 'owner' password (restricts printing, copying, editing). Removing each requires a different approach.
If you can open the file but can't print or copy text, you only need to remove the owner password — Unlock PDF handles this without needing the original password, because the restrictions are advisory, not cryptographic.
Open Unlock PDF, upload the file, enter the password you know, and download the unlocked copy. Takes about 5 seconds.
The unlocked file is identical to the original except the password layer is stripped — fonts, signatures, form data are all preserved.
Modern PDFs use AES-256 encryption, which is mathematically infeasible to brute-force. PDFWix won't crack a password you don't have — and any service claiming to do so for a strong password is either lying or using a cached dictionary.
If you've forgotten a password on your own document, your options are: try common patterns you use, restore from a backup that was unlocked, or contact whoever sent you the file.
On a file you own or have explicit permission to modify, yes. On someone else's confidential document, no — that's unauthorized access.
Slightly smaller — encryption overhead is removed. Otherwise identical.
Yes. Removing the password doesn't invalidate digital signatures.