I use Basecamp now. I love the text doc feature when working with clients. We make a text doc for logins, procedures etc. it lives right there in the project. we can update them and not send email notification - perfect for login info. We can make them private from client and for team only - great for processes/ procedures… Does asana have any option like this?
a google doc is not ideal, but may work.
You can store all this inside tasks. You can have a “Documentation” project and one task for each “subject”