The following document can be used to create contact lists in Office365 email
1. Start by navigating to the “People” tab at the top of your email.
2. Once in the “People” tab, press the “New” button.
3. Choose “Create contact list”.
4. Name the contact list and add members by their full email address. You will need to press the TAB key after entering the full email address for it to be added to the list.
5. After all email addresses are entered, navigate to the “Outlook” field and start a new email. Then use the “+” button in the "To" field to add the contact list.
6. Double-click on the list that you want to email to.
7. Press “OK”.