Do you know what a playground is? It's a place where you can play with your friends and have fun. Now, imagine the whole country is like a playground and there are a lot of rules that need to be made so that everyone can have fun and be safe.
The people in charge of making these rules are called the legislature. They are like the grown-ups who make rules for the playground. There are a bunch of them and they work in a big building called the Capitol. They have meetings where they talk about the new rules they want to make and they vote on whether or not to make them into actual rules.
Some of these rules are about things like how fast you can drive your car on the road or how old you have to be to vote in an election. The legislature helps to create these rules and make sure they are fair for everybody.
There are different kinds of legislature, but the main ones are the Senate and the House of Representatives. They work together to make sure that the rules they create are good for everyone who lives in the country.
So, that's what the legislature is. They are the grown-ups who make the rules for the playground or the country, so that everyone can have fun and be safe.