For Users That Do Not Have Access to the Zoom App
For users that don’t have access to the Zoom App
Navigate to https://myapps.microsoft.com/ (Sign in if required)

Click 

Click Add

Click Add

Click OK
The app can take awhile to appear under myapps but you can, browse to https://www.office.com/apps?auth=2 and zoom will appear under All Apps

Click the Zoom App

Click Sign In