Users can connect by:
Clicking the “Join Teams Meeting” link in the invite – When connecting this way, if the Teams client is installed on their PC it will connect using the Teams client and use PC audio. This is the preferred way to connect users get the full experience. Also, you can connect this way and before joining the meeting there are options for audio, so you could then have Teams call you back or dial in for the audio connection.
Dial in – assuming there is a dial in number, the user can dial into the meeting just for audio.
Mobile client – any meeting can be joined via the mobile client. This allows users to connect over their data or WiFi connection directly into the meeting. This is the preferred way to connect from your mobile device as it gives the full desktop experience right from your device. All screen sharing and chatting can be done from the mobile device just like you were at your desk.