Unlike other Nintendo products, the Wii U hardware does not come with a Club Nintendo registration card. To register your Wii U console in Club Nintendo, please follow these steps.
If you are already a Club Nintendo member:
Connect your Wii U console to the Internet and perform a System Update - this will add Nintendo eShop to your Wii U Menu. Link your Nintendo Network ID to your Club Nintendo account, which will register your console with Club Nintendo.
If you are not already a Club Nintendo member:
Create a Club Nintendo account by registering a piece of software that contains a Club Nintendo registration code, then follow the instructions outlined above.