Step1: Go to: Tool Bar Menu “Tools” ==> Select the Item “Options…”
Step2: Select the “Security” Tab
|Picture of the Excel Sheet Options Window|
Step3: Now Enter the Password for Opening in the “Password to Open” field as show in 2 above.
Other options such as “Password to Modify” can help in protecting from modifications to the file for an added layer or security. The Check box “Read Only Recommended” is to make sure the you don’t accidentally modify the data so excel would ask you in which mode you wish to open the file.
Step4: Press “OK” and then save the Excel Sheet.
This would help you protect you sensitive excel sheet from prying eyes or unintended modifications.