HM Revenue and Customs (HMRC) is like a big boss in charge of collecting taxes and making sure people follow the rules about money. Just like how your parents might give you pocket money and ask you to spend it wisely, the government also collects money from businesses and people who work.
Every year, people have to tell HMRC how much they earned and how much tax they paid. Just like how you might count your money to make sure you haven't lost anything, HMRC checks these numbers to make sure they're right. If they think someone has made a mistake, they might ask them to pay more tax or even give them some money back.
HMRC also makes sure businesses follow the rules about taxes and keep track of the money they earn and spend. This is important because it helps to make sure businesses are treating their employees and customers fairly.
Overall, HMRC is like a big grown-up who makes sure everyone is doing the right thing when it comes to money!