my iPhone call volume is to much low i can not hear my call

These articles may help.

Adjust the volume on iPhone - Apple Support

Also try turning off "Change with Buttons" under Settings>Sounds Haptics (may be just Sounds on your device), that will separate the volume buttons from Alerts and Ringer, in other words the buttons will now only adjust volume for audio (calls and music) and once set should stay set until you adjust again.

Also note you adjust call volume while actually taking a call.