Patents are important for people who create for a living. If you design an invention, it's something you want to protect against others who would copy it and sell it as their own.
Patents can be useful. They protect inventions that are new, useful, not obvious and not a natural process or object. For example, if you design a new kind of water irrigation system, you may be able to receive a patent for your invention.
Is your invention eligible for protection?
Sometimes, it can be hard to tell if an invention can be patented, but that's something that can be determined by the U.S. Patent and Trademark Office (USPTO). What you can do to help is to provide blueprints and information on the invention, including information on why this invention is not like anything else that currently exists.
Once you receive a patent, you will have the exclusive right to sell your invention to whomever you wish. You may also wish to give another company a license to manufacture your invention and sell it. In that case, the manufacturer usually takes a cut of the profits, but it's likely that you'll have a better chance of reaching more people with your invention.
When you receive a patent, it is granted for 20 years. Patents are not renewable, so the products become part of the public domain after that time period. This is what allows companies to make similar products to what were once one-of-a-kind items. However, the 20-year limit does protect you and your initial investment into your product's sale.