"Authentication Method" is a method use to verify a user's identity when the client is trying to access/sign the tax form.
This guide outlines the process for changing the e-signature authenticator as General (applied to ALL clients). If the agent intends to apply for a certain client only, please refer to this alternative guide
Navigate to gear wheel, and select "Settings" then press "Client Defaults"
Choose either SMS or Birthdate, this will be applied for ALL the clients.
You may change the method via e-signature request, window before sending out the esign. Learn more here
Related articles:
How to change e-signature signatory?
E-signature Authenticator (SMS or Birthdate)
Out To Sign: Using E-Signature