How To Join/Leave a Microsoft 365 Group

1. Locate Groups: In the Outlook navigation pane, find the "Groups" section. You may need to scroll down to see it.
2. Discover Groups: Right-click on the "Groups" header and select "Discover".
3. Search for the group: Use the search bar to find the group you're interested in.
4. Join (for public groups): If the group is public, you'll see a "Join" button or link. Click it to join.
5. Request to Join (for private groups): If the group is private, you'll see a "Request to Join" button or link. You may need to provide a reason for joining. 

How to leave

1. Open Outlook: Go to the Groups section.
2. Select the group: you want to leave.
3. Find and select: "Group Settings".
4. Choose: the "Leave Group" option.
5. If you are the group owner, you'll need to designate a new owner before leaving. 

https://support.microsoft.com/en-us/office/join-leave-or-follow-groups-in-outlook-2e59e19c-b872-44c8-ae84-0acc4b79c45d