Add guests to a group
When you add guests, also known as external users, to a group, you're granting them access to all information within the group. This includes emails, calendar, project notes, project files, and project plans. Guests don't see a Groups node in their navigation pane in Outlook but do receive group emails and links to files through their inbox.
The groups header indicates when guest users are included in the group, as shown in this example.
When you invite a guest to join a group, they will be notified by email that they've been added. They'll begin to receive group conversations and calendar events in their inbox. But guest members do have limitations as to what they can see and do in a group. For example, guests can't:
Be group owners
View the global address list
View all information on group member contact cards
View membership of the group
The group owner can revoke guest access at any time.
To add guests to a group
Open Outlook for Windows.
Under Groups in the left folder pane, select your group.
On the Groups ribbon, select Add Members.
In the Add Members box, enter the email address of the guest and press Enter.