Answer:
Flag football is a less contact and safer sport. You have a flag usually on your side or right above your tail bone. If you have the ball and your flag get pulled you are considered "tackled" and the play is over.
NOW in normal football you have pads and a helmet. This version includes ALOT more contact than flag football. Instead of pulling someones flag to "tackle" them you actually have to bring them to the ground. Same basic rules except for the contact part. Any more question on sports just ask me my dude. I got all the answers to sports.