Excel for Chartered Accountants

Microsoft Word 2007 and Microsoft Excel 2007 both have abilities to add digital signatures to it. 
   
Steps for adding a digital signature to MS Word 2007 or MS Excel 2007:
   
1. Insert a text box or simply keep the pointer to the place where you
    want  to add the signature
2. Under Insert menu click on Signature Line > Microsoft Office
    Signature Line

3. In the signature Setup Box, fill the required details and click Ok

SIGNING AND ATTACHING DIGITAL SIGNATURES IN MICROSOFT WORD OR MICROSOFT EXCEL

5. Double Click on the X sign shall open the signature pane

4. The following field shall be inserted in the file:

When a signature is added using this method, it adds both a visible signature (image file of your signature) and the digital signature.

After the signature are added, the file becomes read only the contents of the file can not be altered. To alter the file, signatures have to be removed and re-attached.