Attorney’s will often charge an hourly rate for their services, which range from time in court to depositions to simple phone calls. A billable hours invoice helps the client see exactly what they are being charged for and how much these hours are costing them. Every attorney will invoice their clients differently; they might send an invoice every week or every month or every other month. Regardless of the invoicing period, the transaction will be the same. After the client has received their invoice, they will be obliged to pay the total amount written on the invoice within the given timeframe.