The simple answer is that you have to apply for the show or shows you would like to take part in.
My advice is to tell of something special or weird that has happened to you. The stranger the better and to more chance you have of being invited.
In my case I fell out of a helicopter when in a war zone. I fell about 20 feet but thankfully I only broke my arm.
When I told the game show about this I was invited to appear but decided in the end not to continue.
But when people go on these shows the compare likes to talk to the contestants and if they have something to talk about it goes down well with viewers.
Good luck