In Outlook for Mac, you can create a contact list to let you and others email everyone on the list without having to type each person's email address.
Create a contact list
Select the People icon, and then select New Contact List.
Select + Add to add someone to the contact list, and type their name.
You can add more email addresses, or even a contact list.
When you're done, select Save & Close.
Send an email to a contact list
Select the Mail icon, and then select New Email.
On the To line, type the contact list name.
Everyone on the contact list will receive the email.