Please note that you should have an administrator account in MS365 to perform these steps.
1. Go to admin.microsoft.com and login your credentials.
2. On the right pane of the page.
2.1 Click the “Users” dropdown button
2.2 Then click the “Active Users”
3. You’ll be redirected to the list of active users. Look or search for the user that you want to assign an office license. After searching for that specific user, select the user by ticking the box beside the display name.
4. A pop up page will appear on the right side of the screen that contains the user's information.
5. Click the “Licenses and apps” Tab and select the license(s) that you need to assign.
5.1 Check the “Microsoft 365 Apps for Enterprise”
5.2 Hit the “Save Changes” button.
6. After saving the changes, the license status of the user should be updated as shown below: