Q: Where do I find my license code for old OS X Mountain Lion?

Where do I find the licence code for my MacOS version?

I mean the bought version of MacOS 10.8. I had on my broken MacBookPro.

It should be reusable for another Mac, shouldn't it?

Thanks for your answer.

I did and find the receipt with invoice number and all information related to the purchase.

But I cannot retrieve the licence key.

Where does Apple provide this information within Apple-ID-account or Apple Store account?

Thanks a lot for your answer,

Martin

Thanks a lot, dear Niel, for your information.