How to make this buttons for Android?

Hey, guys. Someone knows why this didn’t work on android ? XD Sorry, i’m new on Unity

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

public class GameController : MonoBehaviour
{
    public string[,] tictactoeArray = new string[,]{ {"?", "?", "?"},
                                                     {"?", "?", "?"},
                                                     {"?", "?", "?"} };
    //Row 1
    public GameObject tictactoeButton00 = new GameObject();
    public GameObject tictactoeButton01 = new GameObject();
    public GameObject tictactoeButton02 = new GameObject();
    //Row 2
    public GameObject tictactoeButton10 = new GameObject();
    public GameObject tictactoeButton11 = new GameObject();
    public GameObject tictactoeButton12 = new GameObject();
    //Row 3
    public GameObject tictactoeButton20 = new GameObject();
    public GameObject tictactoeButton21 = new GameObject();
    public GameObject tictactoeButton22 = new GameObject();

    public GameObject X = new GameObject();
    public GameObject O = new GameObject();

    int round = 0;

    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            if (Physics.Raycast(ray, out hit))
            {

            if(hit.transform.name == tictactoeButton00.name && tictactoeArray[0,0]=="?") {
                    if(round % 2 == 0)
                    {
                        tictactoeArray[0,0] = "X";
                        round++;
                        Instantiate(X, new Vector3(tictactoeButton00.transform.position.x, tictactoeButton00.transform.position.y, tictactoeButton00.transform.position.z), Quaternion.identity);

                    }
                    else {
                        tictactoeArray[0,0] = "O";
                        round++;
                        Instantiate(O, new Vector3(tictactoeButton00.transform.position.x, tictactoeButton00.transform.position.y, tictactoeButton00.transform.position.z), Quaternion.identity);
                    }
                }
                    

            }
        }
    }

    private void OnMouseDown()
    {

    }
}

You used Input.GetMouseButtonDown.
Mobiles dont have a mouse button. Try looking up mobile touch input.