Sound effects
Sound is very important in animation. The type of sounds you use in your film will create the mood. Sound also adds to the meaning of the actions. It makes the film more believable. For example, if you have a character that slams a door, you will need to add the sound of wood slamming to convince the audience that it is real.

Filled Up With Water, by Elka Kerkhofs.

The sound effects are very important in this animation. Use the volume icon and watch it again without sound to see how different it is.

You may like to record your own sound effects for your animation. This is called foley. You may want to put dialogue (people speaking) in your film.
See the Sound section of this website for how to record sound.

 

Music
You may like to set your animation to music. Be careful though. You can’t just use any music for your film. There are rules that govern the use of music in films. You must have the permission of the musicians or the company that owns the piece of music before you can use it. Large productions have to pay royalties (a fee) to the company that owns the music before they can include it in their films. If you know any musicians they may let you use their music for free or they may even compose some for you. Otherwise there are plenty of royalty free music websites where you can download free music and sound effects to use.

Links for royalty free music http://incompetech.com/m/c/royalty-free/ http://www.partnersinrhyme.com/ http://www.neosounds.com/