Simple HTMLr is an Atom package to help write HTML faster by automatically adding bold, italics and underline tags to selections using the standard CMD+B, CMD+I and CMD+U keys.
Just select the text you want and press the CMD+B, CMD+I or CMD+U keys ( Ctrl+B, Ctrl+I or Ctrl+U on Windows ) and the selection is automatically wrapped with STRONG, EM and U tags respectively.
Simple! :)