Regarding multiple log in and password details I use LastPass. It is free and highly recommended in the tech industry. You need to remember one master password to log in to LastPass and it will keep a log of all your log in details, auto fill in if you ask it to and generate passwords.
https://lastpass.com/
I particularly like it because it stores everything in 'cyberspace' meaning I can access it on all my pcs and smartphones. Used it for years without a problem.
If you have just one pc then there is nothing wrong with the written address book although I did smile at the suggestion.
I would create the address book as a file on my pc. Quick and easy to find the details (using the 'find' box), easy to amend and of course you can copy and paste into the log in boxes. This is not recommended if you are likely to lose your laptop. :)