Hello, TreeCityTool
I am Igor and I will be glad to help you with this question :)
To the users be able to join the Teams through a phone number please follow
If there's a phone number and conference ID in the meeting invite (as the attachment), just dial the number to join.
in case you are alreaedy a team member you can:
In Teams, you can call in to a meeting by going to the Calendar Meetings button on the left side of the app, selecting the meeting you want to join, and dialing the phone number provided in the meeting details.
Hope that helps! Let me know how it goes.
i will be available.
Best Regards