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How to Password Protect an Excel or PDF File

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President of OKTO Solutions · 2 minute read · updated July 12, 2026

A payroll list, a client file, a contract: some documents can’t fall into the wrong hands. Adding a password to an Excel file or a PDF is a simple, effective safeguard built right into Microsoft 365.

Quick answer: To password protect an Excel file, open it and go to File > Info > Protect Workbook > Encrypt with Password. Enter a password, confirm it, and save. The same method works in Word under Protect Document. Passwords are case-sensitive, limited to 15 characters, and Microsoft cannot recover a forgotten one.

Password protecting an Excel, PDF, or Word file with Microsoft 365

1. Password Protecting an Excel File

Encrypting a password on an Excel file keeps it from being opened without the code. Here’s how:

  1. Open the workbook, then click File > Info.
  2. Select Protect Workbook > Encrypt with Password.
  3. Enter a password, click OK, then confirm it.
  4. Save the file to apply the protection.

Important: passwords are case-sensitive and limited to 15 characters. Microsoft can’t recover a forgotten password, so keep it somewhere safe.

2. Protecting a Word Document

The process is identical in Word: File > Info > Protect Document > Encrypt with Password. The document becomes unreadable without the password.

3. Password Protecting a PDF

You can create a protected PDF straight from Word or Excel:

  1. Open the document, then go to File > Save As and choose the PDF format.
  2. Click Options.
  3. Check Encrypt the document with a password, then enter your password.

The resulting PDF will ask for the password when opened.

Choosing a Strong Password

A strong password is long, unique, and hard to guess. For business use, a password manager prevents lockouts and strengthens security across the whole team.

Frequently Asked Questions

Can I remove the password later?

Yes. Go back to File > Info > Protect, open the encryption box, clear the existing password, and save the file again.

Does the password also protect against edits?

Encryption protects the file from being opened. To restrict edits only, use the “Protect Sheet” or “Restrict Editing” options instead.

Secure Your Sensitive Data

Need help protecting your data, whether personal or business? Contact OKTO Solutions or check out our services.

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