From PhpCOIN Documentation
If you have never used the invoices part in phpCOIN this is a short briefing of how it works.
First, "Add" an invoice, then when you complete the first screen and hit save, "Invoice Items Editor" will allow you to add billable items to the invoice.
Status: draft | overdue | paid | pending | void What is the status of the invoice? Is it due now, for instance? - Draft (change and send later) - Overdue (invoice has not been paid yet, and it is past the due date) - Paid (client has made a full payment against the invoice) - pending (not due yet, but will be next month/year/whatever. Leave this set if you want phpCOIN to automatically send the invoice when due) - Void (a mistake) Delivered: No | Yes Was it sent to the customer? Must be NO for phpCOIN to send automatically Invoice Date: (year-month-day) When is/was the invoice issued Date Due: (year-month-day) When must it be paid? Anything after this date is considered overdue. Billing Cycle: Weekly | Monthly | Quarterly | Semi-Annual | Annual | Other How often should this invoice be copied to a new invoice and sent? Recurring: No | Yes Should phpCOIN create and send the next one automatically? If yes, it will be a clone of this one as far as the items go. Recurr. Processed: No | Yes DO NOT TOUCH THIS! phpCOIN uses this flag to let itself know if it has automatically sent the next invoice. Total Paid: How much has the customer paid towards this invoice? Best bet is to leave this blank. Please use the "Payment" button at the bottom of the "view invoice" screen to enter payments, credits, etc., which properly sets the "status" field and enters payment transactions into the transactions table. Pay Link: This is the html code for your paypal/2checkout/whatever account if you have one. If you don't use a billing vendor, you might want to use this field for notes: "Your hosting account will expire in 30 days. We will automatically renew the account unless you tell us not to" Terms: What are your payment terms? "COD", "We accept credit cards/cheques only", etc.