- Sign in to Microsoft Office 365 using your Office 365 Admin details.
This would have initially been set up as firstname.lastname@example.org with its associated password.
- On the Office 365 Admin center bar, on the left hand side of the screen, click on "Users" and then "Active Users".
- Select the user you want to reset the password for.
- Click on "Reset password" within the user pop-up window.