You can copy saved game files to a compatible SD card or USB storage device to back up your Wii U data. This process involves accessing the Data Management section in the Wii U’s settings menu, where you can manage and transfer data between the console’s internal memory and external storage devices. Note that while this method allows you to back up saved game data, it does not apply to digital games or software, which must be downloaded directly to the console or an external storage device.