Coat variations can happen within a litter where some puppies are smooth while others are wavy, and again, this all depends on genetics. Here are pictures of two siblings from the same litter, the Merle has a fluffy/wavy coat while the Red one is a "smoothie."
Cockapoos that have the wavy or curly coats also have the well know beard, facial hair, long hair on their ears, and bangs.
Cockapoos with a smoother coat can turn out to be quite fluffy throughout their body, have bangs and long hair on their ears, but often lack the beard, otherwise referred to as "furnishings."
Below is a picture of an adult Smooth Coated Cockapoo, she was recently groomed so you'll notice that her body hair is quite shorter than normal but her smooth face and lack of a beard is a perfect example of a trait very common with the "smoothies."
Here is a picture of another "smoothie" with her hair grown out. You'll see she has a fluffy coat, bangs, and some facial hair on the sides but not a full beard.
I occasionally do get "smoothies" in my litters and personally think that they are beautiful but have come across people who absolutely do not like them, and others who have questioned whether they really were a Cockapoo due to being uneducated about the variations within the breed. If a type of coat style is important to you it is vital that you discuss it with your breeder and wait until the puppies are several weeks old before you pick one. When a Cockapoo is first born they have a smooth coat and their texture develops over time so a breeder will not be able to tell you at birth whether the puppy is going to be smooth, wavy, or tightly curled.
People often ask if smooth coated Cockapoos shed more and the truth is that each dog is an individual with their own traits but all three coat styles have the low to no shedding and low allergy qualities that has made the breed so popular.
It's important to remember that Cockapoos are a mixed breed and will take on the characteristics of both of their parents resulting in different coat styles, different heights, different eye colors, different weights, etc. Please do your research in advance when adopting a pet, no matter the breed, to make sure they will be the right match for you.