How to encode postal zip codes on an envelope
I would like to include postal zip code encoding to address envelopes and mailing labels (the string of lines that appear on the bottom of envelopes that make sure a friend gets all his bills, but only a fraction of his personal mail-greeting cards, etc. Is there an app for this? I tried searching the USPS website, but can't find anything i can understand and use.. I'm using Pages but would consider a word processing program that would allow me to do this on a MacBook Pro. Thanks.
MacBook Pro (Retina, 13-inch, Early 2013), macOS High Sierra (10.13.1)