PWGen is a powerful tool for automatically generating very secure passwords or passphrases.
Why use this? Because the usual alternative is to enter simple words or letter patterns, like "football" or "qwerty" - simple for you to remember, but just as easy for hackers to guess. Use something like "hFMhMdgvQMuatqDm" instead, say, and there's precisely no chance of anyone figuring it out.
Of course you wouldn't remember that, either, but you could always save these passwords in a password manager. Or you can generate passphrases, like "even gassy aura rattle phase", which are definitely more memorable.
Whatever you want PWGen to generate, it won't take long to make it happen. In a click or two you can choose to create passwords or passphrases, select the number of words or characters, even the number of passwords or passphrases you want to create, and then clicking Generate will produce your results instantly.
And the underlying technology is unusually secure. There's nothing written to the Registry, even the program's memory is cleared before it closes down, so there's no chance that anyone accessing the system after you could discover the password you've generated: PWGen is very safe to use.