From Securing your HTTP API with JavaScript Object Signing and Encryption:-
JWT
Basically, the token (JWT) is the simplest structure that you will deal with while implementing JOSE in our architecture; it is a string representation of some data base64 encoded (other types of encoding might be applied, but this is not madatory): the JWT differs from raw base64-encoded data since it also includes informations about the encoding itself, in the token’s header; by concatenating the base64-encoded version of the token header and payload (the actual data) you obtain what the specification calls signature input, which will then be used to create the signature (JWS).
JWS and JWE
After the JWT comes the JWS, which is a signed representation of the JWT; it differs from the token just because of the signature; on an higher step of the ladder comes the JWE instead, which lets you encrypt the data in order to achieve an higher security level: the examples in the ietf draft show you how to create JWEs with a pair of private / public keys.