Adding Alias for Distribution List
A distribution list alias is an email address that redirects all mail to a specified distribution list. A distribution alias is not an email account or distribution list account.
Log in to the console, Click "Distribution List" on the dashboard menu, and select the distribution list you want to add an Alias by clicking the "Gear Icon."

Click "Alias" → "Add Alias";

Enter the distribution alias name you want to add to that list; and click "Create."
Once you add a distribution list alias, you cannot add that email for the distribution list or users; you must delete the alias name before creating a new distribution list or user.

You will see a distribution list alias in the alias list; you can add another by following this article.

Do the test by sending an email using another email account to the distribution list alias that you have created.