# Cryptography Headers in Cryptographic Libraries

I have a question regarding the headings in cryptography. In python, in the pycryptodome module, I am doing symmetric encryption, which asks for a header that goes as follows:

Cipher = Crypto.Chiper.AES.new(key)


My question is, how do I configure the header correctly? I've seen examples of just putting a str, like , and never explaining beyond what they are for, because I should use them, how I should use them, etc. If I need to know how to use them correctly, because I should use them, I understand that they are associated data that are linked or related to the content to be encrypted.