How to Make an Email Group in macOS
If you frequently email the same group of people when you send messages, assemble the relevant addresses into a group in the macOS Contacts application. That way, you can address messages to the group instead of the individuals in it. macOS Mail will send your email to each person in the group. You could enter all their addresses one by one in the To, Cc, or Bcc field. However, making a group email saves time and ensures you include the same people each time you send a group email. Before you can send a group email, you must create a group in the Contacts application and then select people to include. Here’s how.
How to Add Members to Your macOS Mail Group
Next, you add members to the group from your existing Contact entries or add new contacts as needed. When you finish dragging contacts onto the new group, click its name in the group list to see the people you added. To send an email to the group, open a new message in Mail and type the new group name in the To field. That action populates the field with the email addresses of the group members automatically.