How to upgrade a distribution list to a group in Office 365?

Step 1: Sign into Office 365 admin portal via https://portal.office.com

Step 2: Click on Admin from the left pane and navigate to Exchange admin center > Recipients > Groups..

Step 3: Select one or more distribution lists (also called a distribution group ) from the groups page.

Step 4: Select the upgrade icon.

Step 5: On the information dialog, select Yes to confirm the upgrade.