How to add Retention tags for archiving and removing emails so that the users can make use of it in Office 365?

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 Compliance management on the left pane.

Step 6: Switch to the Retention tags tab.

Step 7: Click on the Add icon and select an applying method from the list.

Step 8: Enter name, retention action and period and click Save.