my point is not updating and just keep printing 1 as point even when trigger was apparently "entered

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

public class WhenCollide : MonoBehaviour
{

public int point = 0;

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

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

}

private void OnTriggerEnter(Collider other)
{
    if (other.CompareTag("Animal"))
    {
        point++;
        Destroy(gameObject);
        Destroy(other.gameObject);
        Debug.Log("total point: " + point);
    }
}

}

First of all, you cant have Destroy(gameObject)in the middle of the code. It destroys yourgameObject` and every component attached to it, including your code. So everything after this line will not execute. Then, you are updating variable in the object you are about to destroy.
As I see it,

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

public class WhenCollide : MonoBehaviour {

 public int point = 5;
 // Start is called before the first frame update
 void Start()
 {
     
 }
 // Update is called once per frame
 void Update()
 {
 }
 private void OnTriggerEnter(Collider other)
 {
     if (other.CompareTag("Animal"))
     {
         GameObject player = GameObject.FindWithTag("Player");
         
         // assume you have script called Player with method AddPoints(int points), then
         player.GetComponent<Player>().AddPoints(point);

         Destroy(other.gameObject); 
         Destroy(gameObject);
     }
 }