how to smooth rotation in unity code example

Example: smooth rotation unity

Vector3 targetRotation = path[i].transform.position - transform.position;
transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.LookRotation(targetRotation), 4f * Time.deltaTime);
//LookRotation points the positive 'Z' side of an object in a specified direction
//FromToRotation creates a rotation that from one direction to another direction