Sample invoice template is a legal document which is an essential document to be given to buyer. One copy of invoice is required to be kept with both the parties: seller and buyer. it helps both the parties to keep and track records. For seller, it will help in keeping the records of sold products and for buyer, it will help in keeping the records of received products. Both seller and buyer can check their payment dues and payment paid; if they retain a copy of invoice, with them. Data of invoice may help both parties' if they will trade in future. These records will serve as reference for both of them, and thus saves time. An invoice can be attached with the shipment or sent after the delivery of products. If the trading is done internationally, commercial invoice will suffice and goods will be entered into foreign territory safely. However for domestic trading, it becomes necessary to attach invoice along with the shipment. Rules may vary from country to country.

Now days, generating invoice for a business firm is not a difficult task. There are many billing software programs which not only help people to generate an invoice but also help them in tracking payment records, amount of product received, amount of product due etc. Though an invoice can be easily generated with the help of word processor or spreadsheet, these tools do not help in tracking the product record. It is necessary for seller to mention expiry date of invoice; so that if he has generated the invoice for partial supply of products and after 10 days, he has sent whole order which he was supposed to supply after 30 days; the buyer should not be able to claim for partial shipment of products which he has already received before the mentioned time. Hence seller has to be extra cautious with invoice legal formalities.