You need to know the password
This tool removes a password you already know, so you do not have to type it every time or so you can send the file to someone without sending the password too. It does not guess, test or crack passwords. If you do not know the password of a PDF, ask the person who sent it.
Both the open password and the permissions password work. With either one, the tool decrypts the whole file and saves a copy without any protection.
PDFs that only limit printing or copying
Some PDFs open without a password but do not let you print, copy text or fill in forms. These files are encrypted with an empty open password and a list of limits. The tool removes the limits right away, without asking for a password, so you can print or copy from documents you are allowed to use, such as your own statements or invoices.
What stays the same
Pages, text, fonts, images, links, bookmarks and form fields are kept exactly as they are; only the encryption is removed. A digital signature in the file becomes invalid, because removing the protection changes the file. The work happens in your browser: the PDF and the password are never uploaded, and the password is not stored anywhere.