I'm being really dense here but can't find a megathread for such a simple question so here goes:

my preorder coded

I'm back on my 3rd save to catch it to where a couple of things unlock before a big fight about to happen on my main save and I realised I didn't spend either my physical OR download OR DLC preorder codes yet and I have no idea where to start looking.

The last time I saw them was when I did the order itself months ago and I don't remember if it was on the website, or on my switch or on my email receipt or on an email of it's own? I have tried a combination of several of these already which one have I overlooked or is it somewhere else?