[stumped]

I asked Google which said amazon do not have a policy.
And it is not just amazon. I morbidly realise that I have a lot of stuff that is digital or is on a credit card subscription.
I checked on both netflix and spotify and neither can be funded from a joint bank account using uk direct debits.

Amazon is the main place I have owned digital protected content. But it would be reassuring at our age if all the Netflix type services could be be linked to joint accounts. A credit card can have a secondary cardholder but often that is a simple separate number so not ideal for subscription continuity

There are also the google accounts which own our tablet apps. There's some paid for stuff there

And there's not a lot of point to having stashed a lifetime of family photos in Google and Amazon clouds if the accounts go when I go ! Maybe they should all go onto hard drives in the attic, that seems backward, somehow.