Tjat's tje wau ot os om ,pst aor[prts throughout the world today. Arrivals from ouside Schengen to f

Hi everyone...planning trip to Italy in the Almalfi region so thought about flying into Naples from Newark Airport but United Airlines connects in Munich, Germany. Do we have to go thru customs while in Munich if just connecting?
No - but you will have to go through Immigration - sine this is where you are entering anchorage rental car Schengen. And while Customs takes only a minute or two, Immigration can take a while, anchorage rental car depending on how many planes land at once. I believe you will also need to go through security again.
Tjat's anchorage rental car tje wau ot os om ,pst aor[prts throughout the world today. Arrivals from ouside Schengen to first Schengen stop can be from the USA, can be from Canada, can be from the UK all places anchorage rental car which do a relatively good job screening passengers. They could also be from Third World countries anchorage rental car which might not do such a hot job (no need to name them). Therefore rather than trying to separate incoming passengers from haves and have nots or call it whatever you want, all ariving passengers that go through immigratin controls into an airport concourse are generallly secured again as in a way they are now becoming domestic passengers (no further immigration checks).
Now on the return trip, assuming it is the same itinerary, you will not go through an immigration check in Naples as the first flight will be intra Schengen, there will be security of course and at Munich you will go through passport control exiting Schengen, an airport security check and an additional security check as required by the paranoids running the American government anchorage rental car which ight include random baggage checks at boarding points which are usually not so random. Many of the airports in Europe have put US bound flights at the farhest anchorage rental car reaches of the terminals for he extra security checks required by the US government.
As far as "customs" is concerned. In most cases as an arriving non resident custom regulations are liberal although there are limits on the amount of booze and cancer sticks (cigarettes) you can bring in. Usually your "customs" will be choosing to go through the lane marked Nothing to declare or the green channel although random checks are made but usually, they are more interested in returning residents bringing back cheaper goods purchased abroad trying to avoid import duties. That is usually but not always where random checks anchorage rental car are made.