1Core has provisions to create 3rd party agencies to take care of the subsidy/agency billing scenarios. To create/edit a 3rd party agency, you need to go to the 'Add/Edit 3rd Party Agency' option on the setup page of the center dashboard. 

Access Path : Center Dashboard > Setup > Other > Add/Edit 3rd Party Agency

After selecting the 'Add New' button, you will be taken agency information page where you need to input all the asked details about the 3rd party agency.