How to offer customers spotify vouchers?

[simbob]

A bit of a different question. I have seen in may apps that they offer 3 month spotify premium for free or for some sort of points. After redeeming the points, the customer receives a voucher code which he can use on spotify to redeem 3 month spotify for free.

The customer support forwarded me to the developer guide but I can't find anything related to it.

Does anyone know who I can reach out to, to generate such vouchers which we then can offer our customers?