What is the difference between Courier and Regular Mail?

Regular mail is usually sent through the public postal system. It will take some time before regular mail will be sent, but eventually, it will arrive. Courier mail is going to be different. This is the type of mail that will be sent to people through a delivery service company. There are a lot of people who would choose courier services whenever they would like to receive some packages.
Do remember that while regular mail can sometimes be sent to a postal address, it can be different for courier mail that would need to be sent to a regular address so that the delivery will not fail. Some courier services are trusted more as compared to others.