Who invents new tv shows?

Nobody invents new shows. Only machines, devices, and gadgets are invented. 

A television series or sitcom is developed with a spec script by a writer. The person or the writer will pitch his/her idea to a producer/s and network. Then if it is given the go-ahead and accepted a pilot is made from the spec script. However, they will further develop the series or sitcom during the first season production and shooting. 

Gene Roddenberry pitched his idea of Star Trek to Lucille Ball head of Desilu Studios during a meeting in 1964.

Writers/producers then add the crew- like movies are

The networks hire writers to come up with new shows.

Anyone who wants to.

Varies.  Some may work for a TV company?  One may come up with an idea for one, write it up and send it in and someone likes it?  You could do it yourself these days and put it on this internet!  Tons make just their show and put it on Youtube! 

Pray to GOD about this, if you want to.

Anyone with enough of a budget can make a TV programme and sell it to a channel, technically, though really the same few business people do it who are known to make successful programmes. I imagine it would be hard for an unknown to persuade them. At the end of a programme you usually see a company name and logo, they are ran by ordinary people. Or sometimes the channels themselves invent them.