Passwords is designed to help you store, organise, protect and use sensitive information like usernames and passwords for websites, PINs, bank details, serial numbers etc.
You can create any number of fields (and call them what you like) to save your information to. Right-clicking on a password will bring up a menu from which you can copy the value of these fields to the clipboard.
Your data is stored in a database which can be optionally password protected by a master password. Individual password records can be password protected too, regardless of whether a master password is used.
The auto-complete feature allows you to define a series of data and commands which can then be called to fill in a web form or put data into another application. For example, for a web site login you could create the commands:
Username
TAB
Password
ENTER