Opens right away
Project Cedar
Design review · $1,250
Anyone with the file can read it.
Password Protect PDF Online
Encrypt your PDF with a password to keep sensitive data confidential.
No uploads · No sign-up · FreeAdd a password to a PDF before it leaves your hands
A proposal, financial statement, or personal document deserves a little more care than an open attachment. Set an opening password and save a protected PDF that asks recipients for it before showing the document. Choose a unique password and share it through a separate channel from the file.
Password protection keeps the document closed until a reader has the password. Once opened, it does not prevent that reader from copying, printing, or sharing its contents. Finish page changes with Edit PDF or Merge PDF first, then protect the finished copy.
Best for: Sending a fee proposal, personal records, or a private report to someone who should have access.
FROM FIRST TRY TO FINISHED FILE
How to password protect a PDF
- Choose the PDF you want to protect, or try the sample proposal.
- Enter a new opening password of at least 8 characters and repeat it to avoid a typo. If your PDF needs a password to open, we will ask for its current password after checking the file.
- Select Protect PDF, download the encrypted copy, and open it in your PDF reader to test your new password before sharing.
Protect PDF: frequently asked questions
How do I password protect a PDF for free?
Choose your PDF, enter and confirm a new password, and select Protect PDF. Download the protected copy. You do not need an account, payment, or a desktop PDF editor.
Does the password stop someone from opening my PDF?
Yes. The saved copy requires the opening password to display the document. After someone opens it, they can still copy, print, or share its contents. Only give the password to people you trust with the document.
How should I choose and share a PDF password?
Use a unique, hard-to-guess password or passphrase with at least 8 characters; longer is better. Avoid names, birthdays, and reused passwords. Save it securely and share it separately from the PDF, for example through a different messaging channel.
Can I change the password on an already protected PDF?
Yes. Choose your PDF and we will check whether it needs a password to open. If it does, a current password field appears. Enter that password and set a new one. The downloaded copy uses the new password. If you only want to remove the password, use Unlock PDF.
Will my PDF layout and fillable forms stay the same?
Existing pages, text, images, links, and fillable fields are retained in the protected copy. Open the saved PDF in your usual reader to check it. Changing a digitally signed file can invalidate its signature, so keep the original signed document.
Are my confidential documents uploaded?
No. Your PDF and passwords are processed in this browser tab and are not uploaded to AdaPDF. Use Start over or close the page after downloading your protected copy.
What happens if I forget the PDF password?
AdaPDF cannot recover it. Keep your original file and save the password securely. If you lose the password, create a new protected copy from your original.
Can I encrypt a PDF on a phone or Mac?
Yes. Use a current browser on a phone, Mac, or Windows computer. You can protect one PDF up to 50 MB at a time. Open the downloaded result in a current PDF reader and enter your new password to check it.