Never in this binder: a will, advice, a password, an upload.
Not a will. For that, see a solicitor in the UK or an estate-planning attorney in the US. In the UK, MoneyHelper explains how wills work, for free.
Not advice. It isn't financial, legal or tax advice, and it won't tell you what to do with your money. It's organisation: getting what you already have written down and findable.
Not a password book. It never asks for a password, a PIN or a full account number. Nothing on paper should.
Not online. It lives on your shelf. Nothing to log in to, nothing uploaded, no copy anywhere but yours.
On every accounts page in the kit the line is printed in green: Never on this page: passwords, PINs, memorable words, security answers, full account or card numbers.