How do i change my user name

I’d like to change my username in game because this is not what i wanted when i just started.

I don’t want to stay as powergold lol

Your username is tied to your Xbox account. You can change it once for free if you haven’t already. Just go to your profile on the console and there should be an option to change gamertag.

I don’t have xbox, i just download killer instinct on pc from windows store.

PowerGold is your randomly assigned Gamertag associated with your Microsoft Account. If you access your account on Xbox.com I believe you can change the Gamertag there, or through the Xbox app on your PC.