A land patent is like a special piece of paper that shows someone owns a piece of land. Think of it like getting a certificate that says you own a toy or a giant puzzle. Only in this case, it's a piece of the Earth!
When someone wants to own land, they usually have to buy it from someone else. But in certain situations, the government might give land to somebody for free! Back in the olden days, the government would give land to people who promised to settle and work on it. These people were called homesteaders.
When a homesteader got their land, the government would give them a land patent. This way, anyone who came around later and tried to say the land wasn't really owned by the homesteader could be shown the patent and proven wrong.
Nowadays, people can still get land patents from the government, but they usually have to pay for the land first. They might also want a patent if they inherit land from a family member or if they want to make sure there are no arguments about who owns the land.
So a land patent is basically a special document that shows someone owns a piece of land. It protects them from other people who might try to claim the land isn't really theirs.