If your mic is too quiet, people on calls will struggle to hear you. First, increase the input gain: on Windows go to Settings > Sound > Input > select your mic and raise the Input volume slider. On Mac, go to System Settings > Sound > Input and increase the input level. Move your microphone closer to your mouth — doubling the distance reduces volume by about 6 dB. For headset mics, position the boom 1-2 inches from the corner of your mouth. If your USB mic has a hardware gain knob, turn it up. In Zoom, enable "Automatically adjust microphone volume" in Settings > Audio, or manually raise the input slider during a test call. On Windows, you can also try the microphone boost: right-click the speaker icon > Sound settings > More sound settings > Recording > your mic > Properties > Levels > increase Microphone Boost.