The screen for managing the web console password (or the password for the root account created during Apex One server installation) will only be accessible if the server computer does not have the resources required to use role-based administration. If resources are adequate, this screen does not display and the password can be managed by modifying the root account in the User Accounts screen.
If Apex One is not registered to Apex Central, contact your support provider for instructions on how to gain access to the web console.