Graphics DrawTexture C# Does not appear

I am trying to draw a texture via code like this:

void Update () {
	Vector2 clockSizeP = new Vector2 (clockSize.x * Screen.width, clockSize.y * Screen.height);
	Graphics.DrawTexture(new Rect((Screen.width / 2) - (clockSizeP.x / 2), clockPos.y * Screen.height, clockSizeP.x, clockSizeP.y), clockTexture);

but nothing appears, what am I doing incorrect? TIA

You can only do this during the Repaint event in OnGUI(). From memory you can also do it in OnPostRender but I have not tested that for this answer.

void OnGUI() {
    if (Event.current.type.Equals(EventType.Repaint))
        Graphics.DrawTexture(new Rect(10, 10, 100, 100), aTexture);

It’s a good idea to read the docs before you use a function you don’t know about. At the very least, it’s a good idea to read them after it all goes wrong when you try using something without knowing what it’s for.