In Computer animation, animators use software to draw, model and animate objects and characters in digital area. The process is somehow the same but here we are more free and able to create what we want to create. We can use computer for both 2d and 3d animation. We can also sketch the characters on paper then scan it and import them to 3d software or we can make them using 3d software such as 3ds Max or Maya.
Nowadays we mostly need different software to make our animation, even if we do all the processes in a traditional way; we have to import them to software to see the result.
Of course when we call an animation, computer animation it means that all the process is done in software and it is three dimensional.