Quick Question re:Joint Credit Cards

[Monny]

Is it in anyway possible/allowed for a husband to apply for joint credit card in his and his wife's names but without telling his wife before hand?

The wording in that leaflet is unclear. It does talk about being financially linked but also states:

When two people share and contribute to a household budget, or
have joint credit commitments, lenders need to know about both
partners even when just one of them applies for credit.

This isn't strictly true, for the most part lenders aren't interested unless you're financially linked. Experian provides some great tools for businesses (I've worked in banking for the past 7 years) but it is guilty of peddling misinformation and half truths to promote its credit score service.