Use the dial pad to make a call in Microsoft Teams
On Desktop
The dial pad can be used like a typical phone to make a call to a phone number. (You can also type in names or groups.)
To dial a number from Teams, go to Calls 
, and then enter the number of the person you want to reach by using the dial pad located on the left. Then click Call 
.
To call a person by name, type the name of a person into the dial pad. And to make group calls, enter multiple names and/or numbers, and click Call 
.
To access your dial pad during a call, go to your call controls and select Dial pad 
.
On Mobile
To make a call, tap Calls Calls button >Call and enter a phone number. If you’ve enabled the setting to allow access to your phone contacts, tap Calls Calls button > Contacts Contacts button on mobile devices and select the person you want to call.
Use the dial pad on your mobile device to dial numbers from your personal phone number and to make emergency calls to your country-specific emergency number.