How customer can add few additional fields under the users record listing view who have only the 'Submitter' role access, as customer doesn't have the option to customize the view to add the fields he require for the users who have only submitter roles?

There is a project setting key called ‘Service desk viewrequest columns for service desk user’. To configured additional fields you need to pass the corresponding field ids (from sd_addiitonalparams table) and append it to the setting value with comma separated. For the columns configured using ‘report_table_configparams’ it should be configured using time-52 where 52 being the database id of the corresponding row created for the user defined / computed field in ‘report_table_configparams’ table.