An envelope is a bagged packaging used by people to preserve the contents of mail and exchange document information. Usually rectangular paper bags. It is an indispensable thing in people's lives. Online email is prevalent, but using envelopes to send letters for communication still dominates. When producing printed envelopes, there are strict requirements that must comply with national production standards in terms of size specifications and overall interface. Langfang printing manufacturers strictly require the quality of letterhead and envelope production, and mass produce and sell exquisite letterhead and envelopes to satisfy consumers.