Space warfare is like playing make-believe with your toys, but instead you get to imagine space ships and lasers shooting at each other. In movies and books, people pretend that they're fighting in space with spaceships that are like big airplanes, but they can fly in any direction.
Let's say that there are two groups of people or aliens who don't like each other, and they both have spaceships. They might use their spaceships to fight each other, kind of like how pirates would fight on ships in the olden days. But instead of swords and cannons, they use laser guns and bombs.
When they fight, they might try to damage the other spaceship by shooting at it or crashing into it, and they have to dodge and weave to avoid getting hit themselves. They might use cool gadgets like force fields or cloaking devices to protect themselves or stay hidden.
Just like in real wars, space warfare can be dangerous and people can get hurt or even die. But in fiction, they can also have crazy cool adventures like traveling through wormholes or exploring new planets. And at the end of the day, it's all just for fun and nobody gets hurt for real.