This is the last objective in the Toddler Years. The goal of that objective is to land within 2 feet of the hole but to unlock the achievement you need to actually make a hole in one. This may take you quite a few attempts to make this shot. There is defiantly some luck involved and unfortunately there is no magic secret to accomplish this since there are so many variables involved with the shot. (Wind, aim, swing, etc...)
The best suggestion is to again use amateur settings and use the caddy to assist you with the shot. I have found it the easiest to use the 5 wood which will hit on the front of the green and roll up to the hole. You may need to use some spin to influence the shot as well, but not much is needed as it is mostly a straight on shot. Just a couple of ticks of spin one way or another may be all you need and its possible you may not need to add extra spin at all. I have also noticed it was easier to make it when there was little to no wind or if it was either blowing directly into or away from me. Just keep plugging away at this shot and it should come the more you attempt it as you will being to figure out the exact shot you need to make it in the hole.