What cause the decrease in the use of postal services?​

The evolution of technology is what caused the decrease of use in postal services. People do not need to send letters anymore, as they can simply send a text, email, or call a person in any part of the world that they wish to speak to. It is easier and more efficient, so more and more people are opting to use technology rather than the written letter to speak to people long-distance.
Hope that this helps! ^_^

With technology forever evolving the need for postal service becomes obsolete with tech like drones or bots delivering packages.Mail itself also becomes unnecessary when bills,messages,and advertising can be emailed to people