Integrated Security is the name Microsoft gives to the technology that uses the credentials of your current running session and passes them automatically to the remote resources for authentication.
When activating the Integrated Security checkbox in the User Management window, the password field will be disabled because the operating system will provide a cached copy automatically.
User Management - Integrated Security
When the option is activated, an ellipsis button will either appear or be enabled. Clicking this button will display the Select User dialog.
Integrated Security - Select User
Ensure the appropriate domain is displayed in the From this location field because sometime the location defaults to the local computer. Click the Locations button to be able to browse for the domain instead.
Consult the Permissions topic for information on the rights that can be given to a user.