Do you have to go to collage to be pro football player?

Technically no, but someone without a background of high school and college football will generally not have the knowledge and technique necessary to play professionally. Additionally, it will be extremely difficult to attract a pro team's attention without having the college game to showcase yourself.

Rarely, teams hold open tryouts and an exceptionally athletic person (who normally has played football at a college, albeit possibly a smaller one) may get invited to the scout team.