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You should not set the microphone input volume too high. Most indicators have a red/amber/green indicator to show the volume, you should aim to hit amber levels periodically, for example if you cough. If you are hitting red at any point, turn the microphone input level down. Equally, you should not have it set too quiet, so once you are setup, allow time to check and tweak you audio levels with your fellow participants. All online meetings should have a 'Can you hear me now?' section set into the agenda.
You should not have it the microphone too close to your mouth or nose. Modern headset microphones are focused and of high quality, and will work well if they are placed just under you chin or just above your nose. Nobody wants to hear heavy breathing in a meeting.
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