Follow the below path to enable digital signature in form 16.
Navigate to Payroll >> Admin >> Form 16 >> Click on the Settings Button.
Check the box Whether Form 16 should be digitally signed to enable this option. This option is useful in case Part A is not signed from the Traces website.
Do not forget to Save the changes.
Click on the below link to know how the Form 16 Digital Signer works on greytHR.