Signature

Yes, but do you want to? Without that, the signature isn't removed and can be messy for long threads. Anyway, that's your decision. To remove, use config editor, available at settings>general and scroll to bottom to click that button. Then search for mail.identity.default.suppress_signature_separator and toggle it from False to True.

This question has been locked because the original author has deleted their account. While you can no longer post new replies, the existing content remains available for reference.