Add or remove contacts from a group in Contacts on Mac
You can add or remove contacts in a group. Removing a contact from a group doesn’t delete the contact.
Add contacts to a group
In the Contacts app on your Mac, select contacts.
Drag the selected contacts to a group in the sidebar.
If the contacts don’t go into the group, check the group—you can’t add contacts to a Smart Group.
If you use an Exchange account in Contacts, those contacts can belong to only one folder at a time. Any contacts that aren’t in a folder you create are in the default Exchange Contacts folder.
Remove contacts from a group
You can’t directly add contacts to or remove them from a Smart Group—you must change the criteria of the Smart Group to change who is included in the group. See Create Smart Groups.