When you buy Business Voice, you get the following features and more:
- Phone System - Standard phone features include Voice Mail, Caller ID, call menus, shared phone lines, and emergency calling.
- Domestic Calling - Calls within your country or region are free. International plans and toll-free dialing are also available.
- Audio Conferencing - Lets you host conference calls with people who don't have Teams or don't have an Internet connection.
More information here:
There is an on-going feedback request for SMS/MMS support for Microsoft Teams, you can vote on it over here:
There are third party solutions for this though, for example: