Is this now for the PC or XBox?

If I buy that, it is the key for the PC or for XBox and where do I have to redeem it at all.

Don't look through it at Sea of Thieves.

thanks in advance

It says at the top right

Platform. Xbox life

Is Windows and X box at the same time.

Redeem in the Xbox Life app / launcher

Platform: XBox Live

What will it be?