On an ANDROID ONE running Android 8.1.0 which is the best app for answering incoming calls?

[Android Central Question]

incoming call results:

1- Phone Rings when:
- Display is "on" or "off"
Phone App:
is version 21.0.202664640
The phone app is open or closed

2- The "Help" feature shows-
1-To answer a call, swipe the white circle to the top of the screen when the phone is locked or tap ANSWER.
but DON'T SEE A WHITE CIRCLE or an ANSWER Button

 

[B. Diddy]

Welcome to Android Central! Which phone? Are you saying that when you get a call, you can't find a way to answer it?