Click the Insert tab.
Click the Signature Line button arrow, and then click Microsoft Office Signature Line.
![Click the Insert tab. Click the Signature Line button arrow, and then click Microsoft Office Signature Line.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Click_Insert_Tab_Click_Signature_Li.PNG)
Click Signature Services from the Office Marketplace to sign up for a digital certificate,
or click OK to create your own.
![Click Signature Services from the Office Marketplace to sign up for a digital certificate, or click OK to create your own.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Click_Signature_Services_From_Offic.PNG)
Type information.
Type any instructions for the signer.
![Type information.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Type_Information.PNG)
Select the Allow the signer to add comments in the Sign dialog box check box.
![Select the Allow the signer to add comments in the Sign dialog box check box.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Select_Allow_Signer_To_Add_Comments.PNG)
Select the Show sign data in signature line check box.
![Select the Show sign data in signature line check box.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Select_Show_Sign_Data_In_Signature_.PNG)
Click OK.
![Click OK.](http://www.java2s.com/Tutorial/Microsoft-Office-Excel-2007Images/Add_Signature_Line___Click_Ok.PNG)