why does animation play in unity code example

Example 1: how to play animation with code in unity

public GameObject ExampleNPC;

void Update()
{
    if(Input.GetButtonDown("Animation")) // Make sure to refrence this in Input settings
    {
        ExampleNPC.GetComponent<Animator>().Play("Anim name");
    }
}

Example 2: play animation through script unity

animator.Play("StateName");