Hi, i did the quest (human) on level 15, i did everything (3 quests) but after that, i can't fly anymore and i don't know why? do i have to get that roll document in order to fly all the time?
You can't keep flying at lvl 15. You do quests again at 20, then 25, then 30.
Look through the forum guides to see how to get flight.
Another thing is that you only got a flight scroll which has limited time.