The Mail tab in General Settings allows you to configure how WHMCS sends and manages email. You can choose and configure your mail provider, configure email headers and footers, and more.
You can choose from several supported mail providers for your WHMCS installation, including Google™, Mailgun, Microsoft®, PHP Mail, SendGrid, SMTP, or SparkPost.
You can configure SparkPost, SendGrid, or Mailgun as your mail provider.