You can add a signature requirement to shipments, if the selected service supports this option.
To add a signature requirement:
Select your Service and Package type for the shipment.
Set the weight and package dimensions, if needed.
Select the desired signature option from the Confirmation drop-down.
ShipStation will adjust the rate, if necessary, and you can then create the label.
If there is no Signature option in the Confirmation drop-down, that means the selected carrier or service does not support Signature as a confirmation option.