That way, you might 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.

Open theContactsapp on your Mac by clicking its icon in the Dock at the bottom of the screen.
SelectFile>New Groupfrom the Contacts menu bar.
bang out a name for the new mailing list in the field that appears for an untitled group.

PressEnteron the keyboard to save the new group, which currently has a new name but no members.
Open theContactsapp on your Mac.
see to it the group list is visible in the Contacts app.

If it isn’t, go toView>Show Groupsfrom the Contacts menu bar.
If no email is listed on the contact, that person won’t receive an email.
The name is removed from the group but not from the All Contacts list in the Contacts app.

That action populates the field with the email addresses of the group members automatically.
input your recipients' email addresses, put an address in theTofield, and send your message.
Enter a date and time and tapDone.

Toadd a signature in Apple Mail, go to theMailmenu and selectPreferences>Signatures> your email account.