We use our iPhones (and iPads) for many purposes. For example, we are listening to the music or playing the games. And there is one annoyance: volume. You may set volume by hardware buttons/Control Centre shortcut to low level, so music or game or anything other was not too loud, but it may (based on iPhone’s settings) affect alert volume, so you may not hear a phone call, because sound level was too quiet and you forgot to set maximum volume after listening to the music. Or alert in Clock app was too quiet and you did not wake up. This is really annoying, but solution is very simple.
It’s all in Settings app. So launch Settings app and go to “Sounds”:
Here, under “Ringer And Alerts”, you can set, if alert volume should be affected by volume buttons on your iPhone. Screenshot was taken on my iPhone 6s using iOS 12.
So now, you can enjoy your multimedia without worrying about phone call volume.