Where are my iCloud keychain passwords?

I've got a slight problem with iCloud keychain I'm hoping someone can assist with.

I recently filled out an online form to download some backup software. iCloud keychain generated an auto-password for me on the web form and all was good.

However, I then needed to sign into my account on the backup software app. Haven't got a clue what that iCloud keychain password was and am not too sure where to look next.

THANKS