leave request, user did not receive any notification for the submission.

Summary:

When user submits a leave request, user did not receive any notification for the submission. 
Please advise what to enabled to get an email alert when the request is submitted.

Content (please ensure you mask any confidential information):

When user submits a leave request, user did not receive any notification for the submission. 
Please advise what to enabled to get an email alert when the request is submitted.

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

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