Below is a list of information you should record (if applicable for your website):

• Domain Registrar account username and password
• Web hosting account username and password
• Web Control panel username and password if different from the first.
• FTP webhost, username and password if different from above, and directory name where your web files are stored.
• Any database names and passwords associated with your account.
• All email account usernames and passwords associated with your account.
• Blog (if your webmaster set this up for you) Admin Username and Password.
• Online merchant gateway usernames and passwords.
• Google Local, Adwords, Analytics, etc accounts sign in email address and password.
• Any other SEO service that the may have signed you up for.