So this was a little confusing for me with the new passing mechanic in the game. So there is no low throw mechanic it seems in the newer passing options so you have to set back to classic throwing (can do so in the options screen in game). Get to the 2 yard line in any game and hold LT on the throw to receiver for a TD and the achievement will pop instantly. Easiest pass plays imo to do low throws for are hitch/ hook routes. Hope this helps as its my first guide on the website.