- before you begin the work
- before you finish the work
- if you don’t understand the job
- on delivery of the work
An invoice is a document that you use to charge your customers for their transactions. You have the option of asking for payment before the customer gets the products or services, or allowing them to pay their bill later. Payments may be made in a number of time frames for different types of companies. The customer must pay you within 30 days of receiving your invoice or the product or service, unless you have decided on a payment date. A legislative demand can be used to formally seek payment of what you owe.