hello guys... is it possible to record only the voice, only the sound?

hello

hope all is well and safe in this crazy times

I have three questions related.

1-I want to record myself, and use only my voce. So to have files that are smaller, is it possible to record only the voice? when i go to iphoto, it records caerma and sound?

2-They don't appear in "pictures" in my finder

3- How do we adjest thje volume of the microphone, so. it catches less sound or more?

thank you

tintinnnnn