UIHandler.cs

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

public class UIHandler : MonoBehaviour
{
    public Button btn;
    public GameObject furniture;

    // Start is called before the first frame update
    void Start()
    {
        btn = GetComponent<Button>();
        btn.onClick.AddListener(SelectObject);        
    }

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

    void SelectObject()
    {
        Datahandler.Instance.furniture = furniture;  
    }
}