Question

Inertia force is which force body force or surface force

Answer 1

Inertia is the state of an object that may be in State of motion, rest, etc. when the object is in state of motion then it will be in motion forever unless there should not be an unbalanced force. same application apply in case of inertial rest. so it would both body or surface force as both body can apply force.

Answer 2

It is  one of the body force... ...