Used when you want to send email to group of people without having to type each individual recipient's name, distribution groups are organized by a particular discussion subject (such as "Marketing") or by users who share common work that requires th
Distribution groups are sometimes called distribution lists.
Create a distribution group (list)
Go to the admin center at https://admin.microsoft.com.
Select the app launcher icon and choose Admin.
Can't find the app you're looking for? From the app launcher, select All apps to see an alphabetical list of the Office 365 apps available to you. From there, you can search for a specific app.
Select Groups > Groups in the left navigation pane, and then select Add a group.
On the Choose a group type field, choose Distribution, and then choose Next.
Enter a name, description, and email alias for your new group, and choose whether you want people outside your organization to send email to the group.
Press Add to create a group, and then review your group and choose Close.
To add users to your distribution group, see Add a user or contact to an Office 365 distribution group.
Check out how to use group in Outlook 2016 and Outlook on the web in the Use contact groups (formerly distribution lists) in Outlook topic.
Check out Distribution group issues for help with distribution group issues.