Screens, symbols, and worksheets in the Project Explorer can be password-protected. You can assign individual passwords to each file, or you can assign a single password to all files in the project

Assigning a password to a single file:

1. In the Project Explorer, find and right-click the desired file, and then click Password Protection on the shortcut menu. The Edit Protection dialog is displayed.
2. Type the new password, and then type it again to confirm.
3. Click OK to close the dialog.

The file is now protected. The next time you try to open it, you will be prompted for the password.