How to follow the unit when you click the mouse

Question

I need my unit to move to the enemy when i clicking mouse on enemy and destroy when my unit touch him

For moving i use navmesh and raycast hit

All units have navmesh agent

Enemies moving by points

Answer 1

Lot of ways to do that: i give you the global idea and you adapt to your script i have set layer for enemy to "enemy" just to be sure to chase a clicked enemy. layer enemy = 8 in my sample

3 phases:

First phase: Click detection and trap the gameobject clicked

private bool chasing = false;
public Transform selectedTarget;

    if (Input.GetMouseButtonDown(0))
    {
        //Shoot ray from mouse position
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit[] hits = Physics.RaycastAll(ray);

        foreach (RaycastHit hit in hits)
        { //Loop through all the hits
            if (hit.transform.gameObject.layer == 8)
            { //Make a new layer for targets
                //You hit a target!

                selectedTarget = hit.transform.root;
                chasing = true;//its an enemy go to chase it
                break; //Break out because we don't need to check anymore
            }
        }
    }

Second phase: chase the enemy. so you have to use colliders and at least one rigidbody, you have plenty of tutorial which explains how to detect collision.

    if (chasing)
    {
        // here i have choosen a speed of 5f
        transform.position = Vector3.MoveTowards(transform.position, selectedTarget.position, 5f * Time.deltaTime);
    }

Destroy on Collision with OnCollisionEnter (or InTriggerEnter)

void OnCollisionEnter(Collision col)
{
    if (col.gameObject.tag == "enemy")
    {
        Destroy(col.gameObject);
    }
}

The given code is for 3d game, if you are using a 2d game, just adapt the code to 2D, no difficulties to do that .