Sending Email notifications requires integration with an email server. This is one of the common integrations and the first one in the section.
You can use Turnkey Lender's mail server or enter your own integration credentials. TurnKey Lender support integration with such mailing server providers as Mandrill from Mailchimp, Gmail, Sendgrid, and ActiveCampaign (only for the US). Simulator is available for testing and trial purposes.