Physically, Fultz measures out similar to Dwyane Wade. Here are their pre-draft measurements:
Wade (NBA combine): 6' 4.75" w/shoes, 6' 10.75" wingspan, 212 lb, 8' 6" standing reach
Fultz (Nike Hoop Summit): 6' 4.75" w/shoes, 6' 9" wingspan, 186 lb, 8' 6" standing reach
Some reports have indicated that Fultz' wingspan may now be over 6' 10", but I don't have a measurement that shows that. The Hoop Summit was quite a while ago and he very likely could have grown since then so it wouldn't surprise me. Obviously, he's not built like quite the bull that Wade was, but could probably pack on more muscle as he grows. He's only 18 after all. Wade was 21 years old when drafted.
Game-wise, Fultz' offensive skill-set is basically similar to James Harden or Isaiah Thomas. He can score from all ranges on the court and in a variety of ways. His body control is elite and freakish. Beautiful form on his jumper. Can shoot from range, drive and pull-up, drive to the hoop, drive to get fouls. All of his offensive weapons project to the NBA.