Each payer or insurance has its own payer id number to accept electronic claims. It serves as the electronic address, so the clearinghouse knows which payer/insurance company to send the claim.
Some national payers, such as Aetna (60054), Cigna (62308) and United Healthcare (87726) have universal payer ids that can be used across all clearinghouses. Other payers can have different payer ids based on the clearinghouse.
When searching for a payer id in DrChrono, you can search by payer id number listed on the patient's insurance card (might be listed as EDI number), or by payer name. The payer id will show to the left of the insurance name.
Payer id's that start with PRNT or GPRNT are claims that will be submitted to the payer on paper. Others will go electronically.
Here are links to the payer listing from clearinghouses you may be using through DrChrono:
Carisk Partners (fka iHCFA): http://www.cariskpartners.com/carisk-payers/