To make c365 accessable in your office application your Microsoft Office administrator needs to deploy c365 to you.

You can find the admin deployment guide here:

Admin Deployment Guide

1. Open the office application

2. Click File > Get Add-ins.

   Alternatively, you can also view your add-ins directly from the Home tab by selecting Add-ins.

   

3. Select More Add-ins to explore.

4. In the Office Add-ins dialog, select Managed by administrator tab.

1. Select the add-in and choose Add.

For more references see:

View, manage, and install add-ins for Microsoft 365 programs - Microsoft Support

Or contact your IT-administrator, your local reseller or [email protected]