Replicating McDonald's Mocha
The creaminess in many coffee drinks comes from steamed milk. The milk is heated by forcing steam through it. This leads to a very creamy result. It is hard to replicate at home without an espresso machine with a steam wand. You can foam the hot milk with a cappuccino wand (or something similar) for a slightly more authentic result but the result will not be as creamy as properly steamed milk.