How can I sell and receive royalty payments on an idea or invention i have.

First check patent lists to make sure it hasnt already been invented, or something similar. Then apply for a patent. Getting it made and marketed is a whole other thing. Good luck with that. There are thousands of hopefuls every years trying to get their 'unique' inventions recognized and on the market. It takes a lot of money and most dont make it. Watch a show called 'Shark Tank' if you can.

By definition, royalties are paid to the holder of a patent or copyright. What you need depends on what your idea is:a device or am intellectual idea. A patent is expensive to get because you need to research all related patents, which cannot be done on-line. A copyright is less expensive. I get the impression you are young, so it's probably best to find a sponsor who will fund the development for a share in the rights.