Certified mail is a special type of mail-order delivery service provided by postal agencies. Almost all member countries of the Universal Postal Union (UPU) offer it. It is characterized that the mail is registered from the moment of being deposited in the postal system until its reception by the recipient. During the whole course of the correspondence, the post office monitors the same, allowing the sender to verify receipt by the recipient.
All mail agencies that offer this service deliver a receipt to the sender indicating that the correspondence will be sent by follow-up. It is a more expensive service than the traditional shipment and is usually used in jurisdictional processes or by companies that distribute merchandise and valuables. However, ordinary people can also make use of this service.
When the sender wishes not only to certify the delivery of the consignment but also to leave formal evidence, with legal validity, of the documentary content of the same is used what in Spain is called burofax and in Argentina letter document.
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