Hi, I guess you are looking for Thunderbird Support as Firefox is not a email client. https://support.mozilla.org/en-US/products/thunderbird Or you are using something else which you did not mention the name of. Each program has a unique way to create mailing lists. This should get you off in a direction or idea : https://www.google.com/search?q=how+to+create+a+email+mailing+list+addresses+only&ie=utf-8&oe=utf-8&client=firefox-b G'luck