From the Microsoft add-in store

Step 1

Open the add-in store by clicking on the “Get Add-ins” button.

Step 2:

Find the Trustifi add-in using the search bar and click “Add” to install it.

Step 3

The Trustifi add-in will appear on the top ribbon in your Outlook client.

Note: in some cases, you may need to close and re-open your Outlook client in order to see the add-in.