question

Hi Ronda,  

Call quality on the mobile app is highly depended on the network, very similar to using the desktop app.  The quality of your phone's data signal can make a big difference.  There are a lot of websites and apps that you can use to test your phones signal. 

I personally use an app called speedtest.net on the Google play store but you'll find many choices. 

If you have wifi available, it's a good idea to switch to that network as it will often provide better upload and download speeds.  

Here's an example of two tests that I did. The first one is from a wifi signal, the 2nd from my cell phone's data plan. 

You can also go into the mobile app's call settings and control if/when the device should use Wi-Fi or the RingOut option. (3rd image below)