To select the mic, speaker, and camera you want Teams to use for calls and meetings, click your profile picture at the top of Teams, then Settings > Devices.
Change your default mic, speaker, or camera
Under Audio devices, pick the speaker and mic you want Teams to use by default. Under Camera, select the camera you want Teams to use, and see a preview of that camera's video.
Manage audio settings in a Teams meeting
If people in a meeting can't hear you, you might be muted or you might not have configured your mic correctly. To change your speaker, microphone, or camera settings when you’re on a call or in a meeting, select More options 
> Show device settings in your meeting controls. Then, select the speaker, microphone, and camera options you want.
Make a test call
1. To make a test call, select your profile picture, then Settings > Devices.
2. Choose to Make a test call under Audio devices.
3. In a test call, you'll see how your mic, speaker, and camera are working. Follow the instructions from Test Call Bot and record a short message. The message will playback for you. After that, you'll get a summary of the test call, and you can go to your device settings to make changes.
