The following GL Entry is created when an Invoice is Posted:
CR - Revenue Account: Revenue
The amount for the journal entry is calculated by the Pricing Policies for the product. If there are multiple line items on the Invoice, the above journal is created for each product.
The default Accounts Receivable account has sub-accounts for each customer.
Each product has a Category associated with it. The Category setup defines the revenue (and expense) accounts to be used when creating GL journal entries.