Officially it's ADHD-I (inattentive), ADHD-H (hyperactive) and ADHD-C (combined).
But over here even specialists still often just call it ADD. It's less of a mouthful and more well-known. Personally I also use ADD, as it often saves the hassle of having to explain I'm usually not hyperactive.
It's because the differences between them are less distinct and the names are just more of an indicator of which side you lean to the most for how it affects you.