Log in using the same credentials you use to access your Pokémon GO account.
Enter your offer code.
After successfully redeeming an offer code, a message will display the items added to your inventory.
To redeem an offer code on the web with Pokémon Trainer Club (PTC) accounts:
Offer code redemption on the web is currently unavailable for users with PTC accounts. If you log in using PTC, you can link another login provider to your account and login via that account to redeem your offer code.
To redeem a offer code in-app (Android only):
In the Map View, tap the Main Menu button.
Tap the Shop button.
At the bottom of the screen, enter the offer code in the text field.
Note: In-app offer code redemption is currently only available on Android devices. If you use an iOS device, please use the website linked above to redeem your offer code.
Where can I get offer codes for free items?
Niantic offers a limited supply of one-time use codes in conjunction with special events or sponsored partnerships.