If you hear an echo, use headphones or earbuds during a call. If you hear an echo it's because your patient or provider's speakers are too loud, causing feedback. 

Move to a quieter environment. This will allow your patient or provider to hear your voice more clearly. Move away from other wireless devices that might cause interference.

Ensure no other applications on your device are already accessing your microphone. Otherwise, multiple apps trying to access one microphone input will cause interference. 

Put your device in "Do Not Disturb" mode. Before a call starts, consider putting your device in "Do not disturb" mode If you receive a phone call, it won't interrupt the video session. 

Stay away from wireless headsets. Wireless headsets typically use Bluetooth which can allow for interference. If you notice your patient, practitioner or staff complain about audio quality, try using a USB or inline mic instead of a headset.

Get close to your router. See what happens when you have a call right next to your router.

Mute yourself when not speaking. When you are speaking and the sound comes out of the external monitor (a TV, a second monitor, etc.), the microphone on the computer also picks up the sound and the audio can be garbled. Muting yourself when you're not speaking can help.

Turn the overall volume down. If your audio sounds garbled on an iPhone, turn down the overall sound (rather than having it at full volume).