Mailing list allows you to put multiple email addresses in a list and assign a single email address to send email to everyone in the list.
When you send an email to a list, everyone in that list will receive it. You can also set who can post to a list.
This increases productivity, for example, if you frequently need to send emails to 20 email addresses, you can create a mailing list for those 20 emails and when you are sending an email to all of them, all you need to do is to type list1@yourdomain.com in the ‘To’ field and hit send.