This setting controls how the field for enter the password for a new virtual server appears. The available options are :

Randomly generated password
  A single visible field is displayed, containing a randomly generated password selected by Virtualmin. You can enter a different password though.

Enter password once
  A single field for entering your own password is displayed, with the actual password entered hidden.

Enter password two
  Two fields for entering your own password are displayed, again with the password hidden. Both passwords must be the same.