Open the Excel spreadsheet
Click File
Click Info
Click Protect Workbook
Select Encrypt with Password
Enter a password
Click OK
Re-enter the password to confirm
Click OK
Save the file
Close and reopen the file to verify the password protection
Open the Excel spreadsheet
Click File
Click Info
Click Protect Workbook
Select Encrypt with Password
Enter a password
Click OK
Re-enter the password to confirm
Click OK
Save the file
Close and reopen the file to verify the password protection