If you don’t want to use an add-in in Outlook 2013 or Outlook 2016 for Windows, you can disable it so it won’t show up in your messages.
In Outlook, click File > Manage Add-ins.
Tip: This opens Outlook on the web.
Under Manage add-ins, in the Turned on column, uncheck the box for the add-in you want to turn off.
Tip: To turn the add-in back on, check the same box.