Open the Excel workbook
Click the cell where you want the signature to appear
Go to the Insert tab
Select Text
Click Signature Line
Fill in the signature details
Click OK
Save the workbook
To add a handwritten signature, go to Insert
Select Pictures
Choose an image of your signature
Insert the image into the worksheet
Resize and position the signature image as needed
To sign digitally, open the signature line
Enter your name or select a digital certificate
Confirm the signature
Save the signed workbook