As an Office 365 administrator, you can reset passwords for any users under the Microsoft Office 365 account. To do so, you need to first login as the primary administrative user for Office 365. This user will have the example structure of: newtekone1.onmicrosoft.com. The primary administrative user will always end in .onmicrosoft.com. Other users can be assigned administrative privileges at the discretion of the primary administrator.
2) Click on Users > Active Users
3) Select the User you want to update the password for.
4) Click Reset Password
5) You can choose whether or not you'd like to auto generate the password or create it on your own and whether or not you'll make that user change the password upon login.
6) You can choose to send the newly created password it to a specific email address or you can opt to not have it sent. If you wanting to email the password, put in the email address then select Send email and close. Uncheck the box if you do not want the password email to anyone and then finish.