The European Union is a group of countries that work together to make rules about stuff, like what we can buy and sell or how we share information. These rules are called laws, just like the rules your parents make for you at home.
Everyone in the European Union has to follow these laws, just like how you have to follow your parents' rules. The people who make the laws are called lawmakers, and they work in a big building in Brussels, called the European Parliament.
Some of the laws the European Union makes are about trade, which means buying and selling things between countries. They make sure that everyone is playing by the same rules, so no one country is getting a big advantage over another.
The European Union also has laws about helping people and the environment. For example, they make sure that products we buy are safe to use and that people are paid fairly for their work. They also try to make sure that we're not hurting the Earth too much by being careful about pollution and waste.
If one of the countries in the European Union doesn't follow the laws, the lawmakers can give them a warning and try to help them change their ways. If they still don't listen, they might have to pay money or even leave the European Union.
So, in a nutshell, the European Union makes rules and laws about lots of important things, like trade, people's rights, and the environment, to make sure that everyone is playing fair and doing what's right.