You have 3 seconds from setting the free pass/penalty in which to take it. If you decide that you would prefer another player to take the free pass/penalty, you must place the ball back on the floor.
Do not walk towards a team-mate to pass it to them, as you will be penalised for footwork. Similarly, if you hand it to them, you will be penalised for a short pass.
Any player on the team the penalty was awarded to may take the free pass/penalty, as long as the offside rule is still observed.