Tutorial:Creating a resource pack

Resource packs allow users to include files that can modify or add custom textures, models, animations, music, sounds, user interfaces, and languages that change the way some things in Minecraft behave, look or sound.

There are some things that you should not do when creating a resource pack / texture packs, which includes but is not limited to:

In any case, you should always follow the Terms and Conditions on the Mojang Studios website.