Have an obvious place where we can learn about adding features (example getting Call icon/capability).
We have E3. Haven't been able to find out how to add the calls icon with ability to include people outside my organization in meeting (via phone). I've set guest access for channels and teams but have not found way to add this feature.
Paul Husted commented
Using Calls with recipients who need to join a meeting by phone instead of a Teams app requires one of two things.
Conference calling add-on. Enables adding a conference call-in number to a Teams meeting.
Enterprise E5 license - that includes the conference calling add-on as well as a number of other feature adds.