I’m using my android device to detect the touched position and move my object, but my object change the position way to far it disapears from my camera view, do I need to use ScreenToWorldPoint? It so, how do I use it?
void Update() {
for (var i = 0; i < Input.touchCount; i++) {
if (Input.GetTouch(i).phase == TouchPhase.Began) {
transform.position = new Vector3 (Input.GetTouch(i).position.x, Input.GetTouch(i).position.y, transform.position.z);
}
}
}
Hello!
I think you already know the solution just too lazy for google it. 
transform.position = Camera.main.ScreenToWorldPoint ( Input.GetTouch(i).position );
However if you touch with multiple finger it may cause you a problem. Your object don’t know where to go. You can check in your if statement :
if (Input.GetTouch(i).phase == TouchPhase.Began && i==0 ) {
so you only dealing with the first touch.
also if you want to move multiple object sooner or later. You should check if the user want to move this specific object.
Hope i helped something Best wishes