Remove a PDF password without uploading the file
A password-protected PDF is usually protected for a reason — it is a payslip, a bank statement, a medical result or a contract. Which makes the usual advice for removing that password rather strange: upload the sensitive document, and the password that guards it, to a server belonging to a company you have never heard of.
This tool does not have that shape. The decryption engine is qpdf, compiled to WebAssembly and executed by your own browser. There is no upload step because there is no server to upload to.
Two kinds of locked PDF
It is worth knowing which one you have, because they behave differently.
A document with a user password will not open at all until you type it — your reader prompts you before showing a single page. To remove it here, enter that same password.
A document with only an owner password opens immediately but refuses to be printed, copied or edited. It is still encrypted, with an empty user password, which is why those restrictions cannot simply be toggled off in a reader. Leave the password field blank and unlock it; the file is decrypted and the restrictions go with it.
What this tool will not do
It will not recover a forgotten password. AES-256 with a reasonable password is not breakable by a web page, and a tool promising otherwise would be misrepresenting either the cryptography or what it does with your file. If you have genuinely lost the password to your own document, the realistic paths are recovering it from a password manager or asking whoever issued the file for another copy.
Related tools
To put a password on instead, use Protect PDF. Once a document is unlocked you can merge, split or compress it — operations that fail outright on an encrypted file.