In Microsoft Teams, you can add additional lines to the US by purchasing a calling plan. For more information, see the Microsoft Teams plans page.
For toll calls and outgoing calls, Teams offers different calling plans and credits, and the exact cost depends on the type of plan you choose and your usage. For more information, see the Microsoft Teams calling plans page.
For free calls and outgoing calls, Teams does offer some free options, especially for calling the US and Canada through the audio conferencing service. Under the fair use policy, meeting organizers can make nearly unlimited calls to these regions without deducting from the tenant's credit. See Office 365 Audio Conferencing Extended Dial-out Minutes to US and Canada.
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