You can add a password to an Excel file to prevent unauthorized users from opening or modifying it.

Select File > Info . Select the Protect Workbook box and choose Encrypt with Password. Enter a password in the Password box, and then select OK . Confirm the password in the Reenter …

Add a password to protect your entire workbook and control whether others can open or make changes to it. Protect your file by setting passwords for Open and Modify.

To add a new password, click Protect Sheet or Protect Workbook, type and confirm the new password, and then click OK. To remove a password from the workbook, click Protect …

Setting a password to open or modify a file: You specify a password to open or modify a file. Use this option when you need to give Read-only or edit access to different users.

To prevent other users from accidentally or deliberately changing, moving, or deleting data in a worksheet, you can lock the cells on your Excel worksheet and then protect the sheet with a …

If you don't want content reviewers to accidentally change a Word document or an Excel spreadsheet, you can use formatting and editing restrictions. Note: To further restrict reviewers …

To prevent other users from accidentally or deliberately changing, moving, or deleting data in a worksheet, you can lock the cells on your Excel worksheet and then protect the sheet with a …

Note: Prompting to open as read-only will not prevent changes from being made to your workbook. For stronger protection, set read-only status by locking the workbook with the …

This can be useful for creating a password dialog box, where you do not want the text that is typed in a text box to be "visible". The following information describes how to create this effect.