Redeeming an Code on xbox.xom: Will it Auto-apply to my 360, X1 or both?

It depends on what the code is for. If the code is for a pass for the 360, then it will apply to the 360. If it's for the One, it will apply to the One. The code should state which system it is for.

they will tell you to contact Activision it is BS

If you're talking about the Destiny Expansion Pass, the marketplace item description states "Purchasing this digital content entitles you to both the digital Xbox 360 and Xbox One versions" so it doesn't matter.

On the rewards page, go to your Order history. There you should see the auto-redeem and the ability to get the code. Mine never applies automatically and I have to manually redeem the code shown there.

Hi there Yasir, my name is Gerardo, and I'm an Xbox player, just like you. I'll be happy to assist you with any questions or concerns you may have.

It seems that not long ago, the Game Pass codes obtained through the Microsoft Rewards program are trial codes, not retail codes. With this type of code, it is necessary to have a linked credit/debit card or PayPal in your account to redeem them. This applies both when using the auto-redeem function and manually redeeming the Game Pass subscription reward.

It's important to note that you won't be charged as long as you turn off the recurring billing for the subscription.

On the other hand, remember that when using the auto-redeem function, you will still receive the subscription codes via email, which you must manually redeem in your account. What this function does is use your points to automatically redeem the reward in Microsoft Rewards, but it does not directly redeem it in your account.

I hope this helps and if you have further questions please let me know.

Kind regards,
Gerardo.