Changing the wireless password on your Wii U
Changing your password
From the Wii U Menu select System Settings, followed by Internet.
Next, select Connect to the Internet, then press the X button or tap Connections in the top-right corner.
Choose the WiFi network you would like to configure, then tap Change Settings, followed by Security. Next, select the appropriate security encryption type, enter your password and press OK. You’ll then need to press Save or the B button to save your changes.
If you would like to test your connection at this point, press Connection Test.