If a batsman get bowled on free hit and ball goes to boundary, will four runs be added or not? Is there any rule about this?
When a bowler over-steps, resulting in No ball, and the batsman's wicket has been disturbed with the ball going to the boundary, then 5 runs are awarded to the batting side. Five runs is split as one for overstepping and four for the boundary. All these 5 runs go into the extras (No ball) column. However, if the ball touches the bat/glove before hitting the stumps and then goes to the boundary, 1 run is added in the extras column for the No ball and 4 runs are added to the batsman's score. Either way, the batting side get 5 runs.
13 - Runs resulting from a No ball - how scored
The one run penalty shall be scored as a No ball extra. Any runs completed by the batsmen or any boundary allowance shall be credited to the striker if the ball has been struck by the bat; otherwise they shall also be scored as No ball extras.
Free hit delivery
The delivery that immediately follows the No ball for overstepping in limited overs cricket is a free hit. This means that the batsman cannot be dismissed in any way apart from a run out, handling the ball, hitting the ball twice or obstructing the field. So, if the ball hits the stumps and goes to the boundary, the batsman is not out. Instead the batting team get 4 runs as extras (byes) for the ball reaching the boundary. If the batsman has nicked the ball before it hit the stumps on its way to the boundary, then all 4 runs are added to the batsman's score.
Long story short, if a batsman gets bowled off a free hit and the ball goes to boundary, then yes, 4 runs will be added to the batting side.