As the admin of an Office 365 organization, you may need to add one of your users or contacts to a distribution group
As the admin of an Office 365 organization, you may need to add one of your users or contacts to a distribution group (see Create distribution groups in Office 365.) For example, you can add employees or external partners or vendors to an email distribution group.
Add a user or contact to a distribution group
If you're not using the new Microsoft 365 admin center, you can turn it on by selecting the Try the new admin center toggle located at the top of the Home page.
In the admin center, go to the Groups > Groups page.
On the Groups page, select the name of the group you want to add a contact to.
On the Members tab, select View all and manage members.
On the View Members page, select Add members, and select the user or contact you want to add to the distribution group.
Select Save and then Close.
Learn how to send email as a distribution group in Office 365.