Read-only mode
To prevent other users from modifying your Excel files, set them to open in read-only mode.
Protect specific sheets
One or more worksheets in an Excel file can be protected with passwords.
Protect workbooks
Using a password, you can protect an entire Excel workbook's structure, including the sheet titles, order, and other details.
Encryption
Excel files can be encrypted and decrypted using a password to conceal worksheet data and workbook structure.
Mark as final
To stop further editing, typing, or reviewing of an Excel document, mark the document as final.