We have a Revolut Joint account and top up directly via a standing order as the Joint account has its own IBAN, otherwise you can load it up from your Personal Revolut account. I don't think you can directly top up from a debit card, like you can with a personal Revolut account.
The other thing that annoys me is that spending on the Joint account is excluded from the Revolut analytics for some reason.
Otherwise, we find it works just fine - we each have a card which is linked to the joint account.
According to the terms you can use a third party card. I want to use revolut to pay my mortgage and other utilities that can't normally be paid by credit card from my Lufthansa Miles & More MasterCard to generate miles.
Thanks for answering. The terms seem a little misleading indeed as I went ahead and opened a joint account with my wife and you are 100% correct, there is no option to add money from a credit card, which is disappointing but can be worked around. Too many airmiles to give up just because of a little extra work.