Many programs can be downloaded online that will help with invoicing, including Debitoor, DataVirtue, Zoho, SIWAPP and Softonic. Invoicing programs such as Express Invoice and inFlow Inventory can be downloaded free from Cnet.

Re-invoicing is a financial practice where a company or individual buys goods or services from one entity, then sells them to another at a higher price. It is often used to capitalize on price differences in different markets or to facilitate international trade without physically moving goods. However, re-invoicing can sometimes raise concerns related to tax avoidance or transfer pricing.

The Quickbooks Intuit website has information about online invoicing. The website has a free trial if you are interested in Quickbooks. You can also find a number to reach them at.

Progressive invoicing is a billing method where a large project is divided into multiple stages or milestones, with payments being made incrementally as each stage is completed. This allows for better cash flow management for both the client and the service provider, as payments are not solely tied to the completion of the entire project.

Customer invoices relate to the business as Recievables or income