A persona is like playing dress-up or pretending to be someone else. Imagine you want to pretend to be a superhero, you get a costume, put it on, and then you act like that superhero. Maybe you run really fast or fight imaginary bad guys. A persona is like that superhero costume, but for grown-ups.
Grown-ups need personas when they want to make something for other people. Let's say you are making a toy. You want to make sure kids like your toy, so you have to think like a kid. You pretend to be a kid and imagine what kind of toy you would like. This means you have to think about what the toy looks like, what colors it has, how it moves, how it feels, how easy it is to use, and how it makes you feel when you play with it.
To pretend to be a kid, you create a persona. A persona is like a story about a kid who wants and needs different things. You give this kid a name, an age, a personality, a background, and hobbies. You write down everything you know about this kid, like what they like to eat, what they watch on TV, or what their friends are like.
When you have a persona, you can use it to make your toy. You pretend your toy is for this kid, and you ask yourself questions like, "Would this toy make this kid happy?" or "Would this toy be too hard or too easy for this kid?" If you answer these questions well, then you can make a toy that many kids will like, not just the kid in your story.
Some grown-ups use personas for other things, like writing books or making websites. They create personas for the people who will read or use their stuff. They pretend to be these people and think about what they would like or need. This makes their stuff better because it is made for real people, not just for themselves.
So, a persona is like a story that helps grown-ups make things for other people. It is like a superhero costume that helps you think like someone else. Good personas help you make things that make people happy, just like a good superhero makes people feel safe and happy.