I'm trying to use a code to start Stadia in another account (friend's account), for this account I used a link that led to registration with the 3 month pro period already set. But now I don't have a link but a code to insert and I don't know if once registered with the trial month it will be possible to use it
@ReDellaPadania If my understanding is correct there's currently no promotion for 3 months of Stadia Pro. Can you give more context? Which country are you located, and which promotion are you referring to (please don't post the code)?
Also, is your friend a new Stadia user? Some promotions only apply to new user. Please let me know if you're referring to another issue, since I'm not 100% sure what you're referring to in this case.
Most recent promotions only work with new account registration, so if your friend activated the trial month, they won't be able to use other promotions after that.