Creating A Mail Alias in Website Panel :
1.) Login to your Website Panel via cp.domain.com.

2.) At the center of “User Spaces” area, click on your Hosting plan name”.
3.) Select on “Mail -> Mail Aliases” from DotNetPanel Menu
4.) Click on “Create Mail Alias” button.

5.) Key in necessary information.
Please refer to the following article to know more.
Knowledge Base: To Create A Mailing List in Website Panel