A mailgram is a type of telegraphic message which is delivered to the recipient by the post office.
Each message is placed in a special envelope and dispatched to the local post office for delivery with the mail.
[2] Service via Westar, Western Union's own communications satellite, was introduced in 1974.
The advantage of mailgrams over postal mail is speed and verifiability of transmission.
In the late 20th century they were widely used in official notifications and legal transactions.