When you want to animate a sprite in a PixiJS game, you update its properties inside a game loop. The most common property to change for movement is the sprite's position, such as x and y. The game loop runs many times per second, and each time it runs, you can change the sprite's coordinates. This creates smooth, continuous movement across the screen. By adjusting the amount you add or subtract from the position each frame, you control the speed and direction of the sprite. This technique is essential in game development, as it allows you to create dynamic, interactive graphics that respond to user input or game logic.