The Service Contacts will be a section that loads in your summary that indicates which, if any, service contacts were selected to receive service for the draft/envelope. If no contacts were selected for service, the count will show 0 next to each party (example below).
Also: if the filer selects eFile only, no contacts will receive eservice.
If the party shows a non-zero integer/number, this indicates a service contact(s) is selected to receive a service notification for the envelope. Click the dropdown arrow to the right of the number to view the service contact(s) selected for service.