Exclaimer Cloud uses SMTP authentication when routing your email back to G Suite.
Due to this we require a set of credentials to be specified, during setup.
This account is used to authenticate our service, when we route your messages through our system, and back to Google.
This account does not require any specific permissions, so it can be a dedicated service account created for this purpose and this account can use MFA as long as an App Password is generated for the Wizard. You can set this up using the guide here.