He looks at the talent and type of players he has. If they have a good quarterback they will probably pass more than run. If they have a good runningback they will probably run more than pass. The defense is determined by the size, speed and skill of the defenders. Once the style of play is determined the head coach works with the offensive coordinator and defensive coordinator on the plays they will run.
Offensive styles vary from team to team.
Some teams, like the Green Bay Packers, have a very elaborate offense. Other teams, like the Minnesota Vikings, have a deliberate style. Defensive styles range from very aggressive teams, like the Pittsburgh Steelers, to teams who play it straight, like the Dallas Cowboys. Select one of the strategies and see how they differ. There are other factors in the game of football.