ulem – Package for underlining

The pack­age pro­vides an \ul (un­der­line) com­mand which will break over line ends; this tech­nique may be used to re­place \em (both in that form and as the \emph com­mand), so as to make out­put look as if it comes from a type­writer. The pack­age also of­fers dou­ble and wavy un­der­lin­ing, and strik­ing out (line through words) and cross­ing out (/// over words).
The pack­age works with both Plain TeX and LaTeX.