How to teleport a specific object to an empty?

I want to whenever I click on a cube to teleport to an empty. I know the OnMouseDown and the transform.position but I don’t know how to say to teleport to a specific empty, in C#.
Thank you.

Do You mean an empty GameObject, or some empty position?

If You want to teleport the cube just to position of some empty object, then You should first get position of such object. Ex:

GameObject empty;
//declare empty GameObject called "empty"
Vector3 pos;
//declare empty Vector3
void Start () {
	empty = GameObject.Find ("Empty");
    //Appends actual gameobject called "Empty" to our 'empty' variable we recently declared
	pos = empty.transform.position;
    //Appends position of the "Empty" gameobject to 'pos' variable we recently decalred

//If the "Empty" GameObject is moving, then you should put this into Update() function

void OnMouseDown () {
	transform.position = pos;
    //"teleports" the object to coordinates in 'pos' variable

This will physically “teleport” Your object to any given GameObject called “Empty”. You can read up more on it here: Unity - Scripting API: Transform.position

If You want to append object as a child to an empty object in hierarchy, then You should use Transform.parent, like this:

void OnMouseDown () {
	transform.parent = empty.transform;
        //Appends object that bears the script to gameobject tied to 'empty' variable

You can read more about it here: Unity - Scripting API: Transform.parent