Each payer or insurance company has its own payer ID number to accept electronic claims. It is the electronic address, so the clearinghouse knows which payer/insurance company to send the claim to.
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 the payer ID number on the patient's insurance card (which might be listed as an EDI number), or by payer name. The payer ID will show to the left of the insurance name.
Payer IDs that start with PRNT, EPRNT, GPRNT, or HPRNT are claims that will be submitted to the payer on paper. Claims that are submitted on paper to the payer are charged $0.78/per claim. Others with an all-numeric payer id, are submitted electronically at no additional charge.
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/