Did you decide to design your a2 envelope? if you do, to make your design valid, you need to follow global a2 envelope size. Here are the answers.
Envelopes are still the way to send and information from point A to point B.
The ancient ages, I mean before the internet, People using Envelopes to result from huge needs.
But today it's an old habit more than a need.
But life is to short to investigate of meanless tool's existence.
Just ignore it and stop judging who use those things.
I mentioned A2 envelope size above. Have a good life.