n order to utilize Direct Bill receipt types you must have corresponding companies setup. The minimum required information when adding a new Company is Company Name and Credit Limit. However in practical scenarios you should enter at least Company Name, Contact First and Last name, Address and Phone number.
The Credit Limit field determines the total amount of credit is being extended to the company. If no value is entered it defaults to 0 and Direct Bill receipts cannot be posted. When you enter a credit limit an AR Account is automatically opened for that Company, and Direct Bill receipts up to the available credit limit can be posted.

To add Items to your Quick Charge drop down list, go to  Inventory Items