Hello
Do you want to turn off noise canceling so you can hear your surrounding, or do you actually meant, you want your meeting participants to hear your background noises, this is usually useful when you are a music teacher teaching instrument, for example.
If it is the first scenario, that depends on your headphone, the operation can be done typically on the headphone itself, instruction can vary depending on model.
If you are talking about the latter, you can go to Teams Settings > Devices > turn off Noise suppression. Your computer itself might also have other software like Intel Smart sound or others that requires further adjustment, but see if that works first by turning it off on Teams first.