How to Use HTML in Thunderbird. Thunderbird is Mozilla's free, open-source email client, ... Thunderbird offers a tool that allows you to insert as much or as little HTML code as you want.

Behind the scenes, in the HTML code, the headline is wrapped in an H1 tag. This page has a headline and several sub-headings to break up the copy into sections. Those sub-headings use H2 tags, the ...

Instead, you must use HTML code to enter spacing between your lines. The most basic of these are , which introduces a single-spaced line break, and. Advertisement. Article continues below this ad ...