The consultant hourly invoice is used to bill a client by the hour for consulting services, such as marketing, human resources, strategy, financial, etc. The billable amount per hour should be negotiated before the consultant begins their work and, once the work is complete, the invoice should be sent to the client so they can look it over. The total hours spent consulting will be marked on the invoice as well as the total amount that the client must pay. The consultant will give the client a certain number of days to make the payment. The consultant and the client should keep a copy of the invoice for their records.