Buy Mafia III: Definitive Edition (GL) with crypto

Launch the Steam client and sign in to the account where you want the game to stay permanently — the key is bound to this account and cannot be transferred.

In the client's top menu, open the "Games" section.

Select "Activate a Product on Steam…" and click "Next" after accepting the agreement.

Paste the received key into the "Product Code" field and confirm — Mafia III: Definitive Edition will appear in your Steam library, where you can install and launch it.

Via browser: open store.steampowered.com/account/registerkey and sign in to the same Steam account.

Enter the key in the field on the registration page, accept the agreement and confirm — the game will be added to the account's library; you can download and launch it only through the Steam client on a PC.