Blogger's text formatting buttons only officially work in Internet Explorer 5.5+/Windows, and the cross-platform Mozilla family of browsers (Mozilla 1.6+ and Firefox 0.9+). Meaning, we've fully tested them in these browsers. We recommend that our users use the latest release of Mozilla Firefox.
These editing features rely heavily on javascript, and will hopefully work in more browsers as they are developed and enhanced. When this is available, Blogger will support it.
For a more complete list of which features are supported by which browsers, please see our Blogger Browser Matrix.
If you are using a supported browser, make sure that you have the Compose Mode option set to "yes" on the Settings | Basics tab. Then your posting form will show both Edit HTML and Compose tabs. The Compose tab contains all the formatting options.
