In the unorganized world, we change our postal addresses much more frequently than they used to in the organized world when many more people lived and worked in the same place for many years. These days, we move around as we change where we work, travel and study. If I want all of the calls made to my personal number to arrive on my home phone rather than my office number, I can get the calls re-directed by letting my telephone network know.
Every individual gets an address for life and can be reached through it forever.
Currently, all that is available is the concept of Post Office Boxes which are organized on a local basis, just like Standard Telephone Dialing Codes. You can change where you live within the local area without changing your post office box address, but if you move cross-country you have to change address and box number. You could issue everyone with a unique number depicted by one of the machine-readable bar coding standards that have been adopted. These days, laser printers can routinely print barcodes. Even Optical Character Recognition of handwriting could be used when letters are scanned through posting machines.