Okay kiddo, so when you go on a trip to a different country, you sometimes have to pay something called a "departure tax." This is like a fee that you have to pay before you leave that country and go back home.
The reason they do this is because the government of that country wants to make sure they still make money even when you leave. It's kind of like when you go to a store and you have to pay for your stuff before you can take it home.
Now, the amount of the departure tax can be different depending on which country you're in and which one you're leaving. Sometimes you don't have to pay it if you're just taking a short trip or if you meet certain requirements. But usually, you'll have to pay a little extra money before you can leave.
So, if you're ever traveling somewhere and you hear about a departure tax, don't worry! It's just something you have to pay to make sure you can come back home safely.