The Teleport Access API provides a simple email access request plugin that sends email notifications to specified email addresses or distribution lists when an access request is created. You can find the Teleport Access API in the main Teleport repository and examples of access request plugins in github.com/gravitational/teleport/api/integrations/access/.
If you have a self-hosted Teleport deployment, you can find information for configuring this access request plugin in Teleport Access Requests with Email.