Transform.RotateAround

Description

Rotates the transform about axis passing through point in world coordinates by angle degrees.

This modifies both the position and the rotation of the transform.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Update()
    {
        // Spin the object around the world origin at 20 degrees/second.
        transform.RotateAround(Vector3.zero, Vector3.up, 20 * Time.deltaTime);
    }
}