A fax is a copy of a document that has been scanned and sent via a telephone line to the receiver. It can be used to send documents in a very short amount of time but only if there is a hard copy to hand. This can also be used for Tesco if a contract or agreement needs to be signed.
You can use a fax to get information out and to communicate with a number of recipients these may include customers, suppliers and employees. For example a fax could be sent to a customer with information regarding their orders. This is a suitable method for that as it is quick and faxes are often used by business to send an order to their suppliers however faxes are slowly being taken over emails.