Here’s an article on how to install noise gate plugin in Audacity.
Breaths marked with a red rectangular in Audacity How to remove breaths with a Noise gate in Audacity? However, breathing noise can be removed using a noise gate, amplify or noise reduction tools within Audacity. Since the diaphragm within the microphone is sensitive that causes a loud distorted sound.
Breathing noise is caused by air puffs coming from your mouth and hitting the microphone.