If others can't hear you in Microsoft Teams, check your audio settings in Teams.
Set Active Microphone
Click on the "Settings" button (cogwheel).
Select Devices.
Select your active microphone from the drop down menu.
Click Make a test call to make sure your settings are correct.
Advanced: Sounds Settings in Windows
Check that Windows can see your microphone. This process is a little more advanced than the others, but it may prove useful if you're still having trouble
Right click on the Speaker icon on the right side of your task bar
Click on Open Sound settings
Click on Sound Control Panel under "Related Settings"
In my screenshot, the Related Settings are on the right; however if your window is skinnier, you will have to scroll down to see the Related Settings.
In the pop-up window, click once on the microphone that you are trying to use for Webex or Teams. If it has a green checkmark next to it, then Windows already sees it as the default device and it is the device Windows is trying to use. From this screen, you can see the level that the microphone is picking up. Try speaking into the microphone and watch the level meter to see if the level raises in response to your voice.
You may click on the Properties button to further investigate the problem. Click on the Listen tab
Click on the checkbox in the window to enable the Listen Feature. This will play whatever the microphone picks up through your speakers. Be wary of feedback loops!! Here you can hear for yourself what exactly the microphone is hearing. Be sure to uncheck this box as soon as you are done with this step.
The next tab you can check is "Levels". This tab contains a volume slider for your microphone just like you have for your speakers. Try raising this if needed.