Thunderbird sets the automatic signature and reference location for email replies.

By default, Thunderbird replies or replies to emails. Sometimes, the reply content and signature are under the email content, which is different from the traditional thinking of reading emails, therefore, you need to set it in the following way:

Select "edit"-> "account settings"-> current account-> "manage identities" in the lower right corner-> select "edit" in the pop-up box ", in the new dialog box, select the tab "Composition & addressing ",

Select "automatically quote the original message when replying", then "start my reply above the quote" and place my signature "below my reply (above the quote )"