When sending an email from your app, especially to the public, it is important to provide users with options to do the following:
Opt in to or out of email notifications
For example, an opt-in toggle displayed clearly in your app.
Unsubscribe if users want to stop receiving emails
For example, you might provide a link in your email that navigates to an unsubscribe view in your app.
Email services are sensitive to complaints about spam that does not require opting in or allow a user to unsubscribe. Failure to implement these options may result in your emails being blocked by an email service provider.