Zips are not really used in Israel, don’t worry about it.
Actually, most people are not using the post service these days because mail is unlikely to arrive in a timely manner. Wedding/bar mitzva invitations, are either hand-delivered or emailed. There are delivery services/gemachs just for that purpose. I just heard that companies like the electric company have even hired special delivery services to deliver the bills since they were arriving after the pay-by-date.
Just went to the post office to pick up some registered mail. Got the notice that it arrived at the end of last week. It was dated Dec 20- took a month to arrive! Meanwhile, the package had already been sent back to the sender.
And by the way, I am not a descendant of Yosef Hatzaddik. We come from Levi. Yosef’s descendants were exiled with the 10 tribes and are lost.