This service shouldn't need any introduction; Ansible can be configured to send emails using all sorts of configuration. The following example shows an email being sent through an external SMTP server:
- name: Send an email using external mail servers mail: host: "{{ mail.smtp_host }}" port: "{{ mail.smtp_port }}" username: "{{ mail.smtp_username }}" password: "{{ mail.smtp_password }}" to: "Russ McKendrick <russ@mckendrick.io>" subject: "Task Success" body: "The task has completed and all is well" delegate_to: localhost