There are 2 places you are prompted to provide login information within Umango.
The first is a one-time request when you install the product. This sets the service logon account as explained in the dialog and is a "set and forget" that can only be changed within the Windows service properties:
This account provides the user permissions to perform background functions such as reading and writing files, performing LDAP lookups etc. The account can be set to a domain account or a Windows user account configured on the Umango server. Typically this account has some elevated privileges as it needs to do things that a typical user account may not.
The second login prompt is seen when a user opens Umango in a browser or a mobile device:
This account provides the user session their permissions within the dashboard. The account is a domain account or a Windows user account on the Umango server. Typically this account is the account a user would logon to their computer with and identifies them within the organization or domain. By the user identifying themselves, documents processed within the dashboard can be assigned to them and enables the user to keep track of things and view the relevant history and queues that are their own. Where implemented, it also enables them to see jobs that have permissions assigned to them or their user group.
Link to this article http://umango.com/KB?article=99