Don't have Digital Signature option under Signature Fields

I am on Adobe Sign Pro free trial. I don't see Digital Signature option under Signature Fields. According to: Use digital signatures (adobe.com).  It says The admin needs to enable it under Account > Account Settings > Digital Signatures. But our admin console doesn’t have account setting option. Maybe because we only have the trial version? Just want to make sure the paid version does have Digital Signature option so our user can request digital signature. 

Thanks