“Ability to let others open the same secured document using their own password without any prior arrangement”
Yes, that’s right!
What this means is that if you share an encrypted file with me (another user) then I can open that file with my password. If you choose not to share the file with me, I don’t have access. Even if I managed to get hold of the file from your computer it’d be useless, because I’d need your password.
Sharing an encrypted file simply re-encrypts the file using my public key. AxCrypt does all of this automatically in the background. It removes the problem of having multiple passwords because you could share an encrypted file with a dozen different users and then revoke access of the file to all/some of the recipients.
If you want an even simpler answer, watch the official video: