Check it
Open Profile → Redeem promo code. Enter the code and choose Check code.
Follow the result
Some codes show Claim promo and a confirmation. A checkout discount instead offers Choose a plan so it can be applied to the payment flow. A valid-code preview is not, by itself, a completed redemption.
Verify your access
After a successful claim or confirmed checkout, open Subscription and review the resulting status and features. Read the error shown if a code is expired, ineligible or already used.