is it possible to set up a company as both a vendor and a customer, to invoice for referral fees

Yes, it is possible, @jb583. You can add it as both a customer and a vendor in QuickBooks Online (QBO) by slightly altering the name, since QBO doesn't allow duplicate names in the system.

You can follow these steps to start adding them as vendors:

1. Go to My Apps and hover over Expenses & Bills.
2. Select Suppliers.
   
3. Click Add Supplier or New Supplier.
4. Complete the fields in the Supplier information window.
5. Select Save.

Then, add them as a customer with an alteration to their name. For example, use John J. Doe if the vendor's name is John Doe.

Feel free to reply if you have more questions about QuickBooks. We are happy to help.