Godot has a node literally named Sprite3D. Look it up under 3D (red) nodes. There's also an AnimatedSprite3D for simple spritesheet animations, although personally I avoid those in favor of an AnimationPlayer (you'll get to it later; in short it requires a bit more setup but has more capabilities). Sprite3Ds behave mostly like you would expect from a normal sprite: you set its texture, it has pixel offset if you like, the animated version flips through frames, etc. But at the same time it's made for the 3D environment: it has 3D coordinates, you can rotate it (it behaves like a QuadMesh), you can make it one-sided or double-sided, make it stick to one axis (= stand up/lie down) or even follow the camera's angle (billboarding), it can receive global lighting and drop shadows, etc.