This is typically done for insurance companies running through Safelite.
Go to Company > Insurance Company Maintenance, and chose the insurance company. As an example, lets pick on SAFECO. Look at the EDI section of the insurance screen and select the Trading Partner ID of 044 Safelite. In the EDI Assigned ID field directly below, use the pull-down menu find SAFECO and save-it.
Setting the Insurance Company this way will 'load' the Program ID on the Safelite EDI screen with the correct Program ID. Using this method will avoid EDI rejects for a Missing Program ID