First Class Mail
First class mail should be used when sending correspondence, postcards, bills, statements of account, money orders, and checks which weigh less than 13 ounces. First class mail that is not letter size must be identified as "First Class Mail." For mail over 13 ounces Priority Mail offers expedited delivery of first class mail when the speed of Express Mail is not needed. Mail weighing less than 13 ounces may be sent Priority Mail provided the Priority Mail Postage is paid. Priority Mail pieces should be placed in special Priority Mail envelopes or marked with Priority Mail stickers or imprinted with a rubberstamp. Supplies are available from Mail Services or from the U.S. Post Office.
Mail provides a guaranteed overnight delivery of urgent letters and packages to
most locations in the
Certified Mail vs. Registered Mail — Certified Mail provides you with a receipt at the time of mailing and a record of delivery. Certified is a good choice when you want to prove that you mailed something and that it was received. Items travel as First-Class Mail.
Registered Mail is a highly secure form of delivery that is documented at each step of the way. Registered mail is best for sending documents or items that have an intrinsic value, where security is important. This mail is kept under lock and key during its journey. As a result, it takes longer to reach its destination.
Because of misunderstandings, Registered Mail is sometimes used by mailers who really do not require such a high level of security. Consequently, registry fees are spent and can inflate postage budgets.