Unity about conversion between local and world coordinates

The common one is transformPoint This kind of API Refer to the
The code I wrote is attached below

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CreateCube : MonoBehaviour
{
    
    // Start is called before the first frame update
    void Start()
    {
    
        
    }

    // Update is called once per frame
    void Update()
    {
    
        
    }

    [ContextMenu(" Create empty object in front left ")]
     void TestFun1()
    {
    
        // Vector3 pos = this.transform.TransformPoint(new Vector3(-1, 0, 1));
        GameObject obj = new GameObject("hello");
        obj.transform.position = this.transform.TransformPoint(new Vector3(-1, 0, 1));

    }

    [ContextMenu(" Reluctantly create 3 A sphere ")]
    void TestFun2()
    {
    
        GameObject objOne = GameObject.CreatePrimitive(PrimitiveType.Sphere);
        objOne.transform.position = this.transform.TransformPoint(new Vector3(0, 0, 1));

        GameObject objTwo = GameObject.CreatePrimitive(PrimitiveType.Sphere);
        objTwo.transform.position = this.transform.TransformPoint(new Vector3(0, 0, 2));

        GameObject objThree = GameObject.CreatePrimitive(PrimitiveType.Sphere);
        objThree.transform.position = this.transform.TransformPoint(new Vector3(0, 0, 3));


    }
}