Most style guidelines strongly recommend against using underlines in print. Underlining used is for emphasis in handwritten material, because it's difficult to

Most style guidelines strongly recommend against using underlines in print. Underlining used is for emphasis in handwritten material, because it's difficult to hand-write italics, much less bold. In a printed context, it just looks... unprofessional. Of course, this is a stylistic preference and not a normative linguistic imperative, because I detest such things. But it's a very common one.