Teams Phone
User users can use Teams to place and receive calls, transfer calls, and mute or unmute calls. Teams Phone users can click a name in their address book, and place Teams calls to that person. To place and receive calls, Phone System users can use their mobile devices, a headset with a laptop or PC, or one of many IP phones that work with Teams.
Every user has their own DDI number (option to display company number when making outbound calls) and all existing DDI numbers can be transferred to Teams Phone.