How to check the sender of an old envelope

Look at the mailing address.

Registered mail can be checked through the registered mail receipt, which is a document with a row of barcodes and English and numbers below it that you get when sending registered mail. You can inquire by presenting your letter receipt at any post office. I found out for you that the anonymous letter was sent from a mailbox that cannot be found. You cannot find out who sent it.

For anonymous letters, you can look at the stamp of the post office and find the post office branch. When you get to the branch, you can find the source of the letter. You can only determine which post office branch the letter was received from. If you want to know who it is, only law enforcement agencies have the right to investigate. If it was just a letter that was not illegal, no one would bother to check it. But if it involves illegal activities and the public security organs want to investigate, it will be easy to find out.

What does an envelope refer to?

An envelope generally refers to a bag-like package used by people to post letters and keep the contents of letters to communicate document information. , envelopes are generally made into rectangular paper bags. Also refers to the envelope basin (Sichuan Basin), also refers to the "envelope" of books published by Yilin Publishing House, and also refers to Trojan envelopes, such as QQ envelopes.

Envelopes generally use 80g-150g offset paper and kraft paper (natural kraft paper, white kraft paper). Depending on the function, art paper, coated paper, etc. are also used. The operation of the envelope machine requires that the paper must have high tensile strength and tearing strength to avoid paper breakage and cracking. It is best to use offset paper because offset paper absorbs ink.