"Vinyasa" means "flow" and so if a class has the word Vinyasa or Flow in the title you can expect the class to focus on extended moving sequences coordinated with your breathing. Some teachers work with faster more energetic sequences, some with smoother slower sequences.
Vinyasa classes tend to be constantly moving with no pauses. A Flow class is likely to have breaks between sequences, but how it's structured is up to the teacher.
It's likely that you'll break a sweat, and leave feeling like you've had a good workout.