How to restrict an Office 365 account from accessing via a specific device?

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

Step 2: Navigate to Exchange admin center.

Step 3: On the left pane, scroll down and click More features.

Step 4: Click open under Permissions.

Step 5: Click Mobile on the left pane.

Step 6: Click the Add(+) icon respective to the Device Access Rules area.

Step 7: Select the device family, model and restrictions and click Save.