To get your NBA 2K19 Locker Codes, you need to go through the steps here
Once you are at the homepage, tap or click the Get Locker Codes
Then, Choose your game console example (XBOX One).
Next is to Choose your Reward either Virtual Currencies or Diamond Player Code.
Final Step is to Prove that you are human, finish by entering valid information. Details like email address matter.
It is to ensure that the code is delivered to the right person.