YOU DON'T! The only people who would legally have a Wii Points Code Generator would be Nintendo themselves as they would be the company that would create & authorize the prepaid Nintendo Points cards that the codes would be for. Therefore, it would illegal for anybody outside of Nintendo themselves to be in possession of such generators.
Additionally, anybody who claims to have a "working" code gen is likely fake as Nintendo has the "MASTER LIST" of all active, outstanding codes for Nintendo Points. These outside code gens are nothing more than a brute-force attack in an attempt to luck out & hit one of those unredeemed cards.
The effectiveness of Wii Points code generators become increasingly ineffective as Nintendo discontinued the prepaid Nintendo Points cards around 2012 (when they discontinued WiiConnect24 services, but NOT NWC services)... making the only way to get Wii Points is to purchase them directly online via the Wii Shop channel.
Therefore, you should just give up as all you're going to do is waste your time on this fool's errand.
I know this isn't the answer you want to hear, but it's the harsh truth that you'll have to live with.
