Email notification on Subscription Activation

Summary:

We want to send email notification to subscription contact once the subscription activated.

Content (required):

Once the subscription is activated, we want the customer contact to receive the email notification with subscription details. Could not find anything relevant in the documentations. Please let us know the approach if anyone have implemented this before.

Thanks in advance.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):