A cortado is typically made with equal parts espresso and steamed milk (2oz of espresso with 2oz of milk). The milk in a cortado is not as frothy as that in a cappuccino, but it's still enough to soften the intensity of the espresso without overwhelming it.
A macchiato is a delightful espresso-based drink that consists of a shot of espresso "stained" or "marked" with a small amount of frothy milk (a scoop size). The result is a bold and intense coffee flavor with just a hint of creamy texture.
A flat white consists of a double espresso and about 4oz of steamed milk with a very thin (5 mm) layer of microfoam. Its name originates from the thin layer of microfoam, as opposed to the significantly thicker layer of foam in a traditional cappuccino.
A latte, short for caffè latte, is an espresso-based drink that typically consists of one or more shots of espresso and a larger amount of steamed milk. The ratio of espresso to milk in a latte is typically around 1:3 or 1:4, depending on personal preferences.