Registered mail

Registered mail is a paid system that records a letter and keeps it secure through the mails and on to the receiver. Typically, a number is assigned to a letter or package for that purpose and someone must sign for it.

Special markings, typically with "R", are used to mark such mail. This can include a handstamp or label that will include the number.

 File:US 1954 regd cover.jpg|A 1954 US registered airmail cover with return receipt requested. Note the "R" handstamp with the registration number. The back view (bottom) has mailing office postmarks struck to detect any tampering. The receiving office postmark is struck on the back as well. File:Russia Riga regd cover.jpg|1953 Soviet Union cover, Riga to Vienna, Austria. Russian marking at upper left above the registry label, "RECOMMANDÉ" also handstamped per UPU rules. 

Special stamps have been issued for the service.  File:NSW reg.jpg|New South Wales. File:US registration.jpg|United States. 