How to Put a Signature on Microsoft Excel. Microsoft's Office programs have powerful options for creating and editing documents as well as protecting those documents.

You may already know you can add a watermark to a Word document, but you might not know that you can also add a watermark to an Excel sheet. Here's how.

Want to protect an important Word document or Excel spreadsheet? Here's how to add a password, make documents read-only, and tap into other tricks to safeguard sensitive files.