Oh boy, have you ever wanted something to happen and then asked someone else to make it happen? That's kind of like a causative sentence!
You see, when we use a causative sentence, we are asking someone else to make something happen for us. For example, if you wanted to eat tacos but didn't know how to make them yourself, you might say something like "Mom, can you make tacos for dinner tonight?"
By asking your mom to make tacos, you are causing the tacos to be made even though you are not doing it yourself.
Now, sometimes, we don't just ask someone else to do something for us, we make them do it. This is kind of like when your mom makes you clean your room. She is causing you to clean your room because she is making you do it.
Overall, a causative sentence is when we ask or make someone else do something for us, causing something to happen that we wanted.