Summary. By default, Mozilla Thunderbird is configured to begin your reply below the original email. Follow these instructions to change the setting:

  1. From the Tools menu choose Account Settings. Your email service/server name should be listed on the left with various setting categories below it.
  2. Click on Composition & Addressing.
  3. Select the option “Automatically quote the original message when replying…” and “Then start my reply above the quote.”