The answer to your question probably depends on what you have connected to the Arduino.
Connect 5V from Pi to 5V on header, Gnd to Gnd
Is the USB also being used for communication?
Will that give more power than the usb?
Also will there be a problem if i use the usb for my communication?
That could be a problem. You may want to remove the PTC fuse next to the USB connector so the RPi is Not attempting to power the USB in your computer if the computer voltage happens to be low.
I intend to connect sensors on the arduino,wheel encoders,HC-SR04 or the lidar lite V2, and maybe a servo.
Whoa there, a servo is not a sensor!!, and its definitely not powerable from a Pi....