KeePass is a password manager that helps to keep all passwords in a safe environment and access all of them using a master password or a key file. Is recommended to have different passwords for each account (website, forum, email, bank etc.) and to have strong ones. Instead remembering all passwords (which may be impossible), you need to remember just ONE password to access KeePass interface. Once you are logged in, you have access to all your passwords.
Passwords can be easily stolen by viruses or persons who access your computer. Storing them in a password protected application such as KeePass, will make impossible these kind of things. Only you or who knows master password will have access to all stored passwords.
It includes a password generator to create strong ones for your different accounts. You can import or export a list with passwords from/to TXT, CSV or HTML formats.