A friend of mine uses pdfLaTeX for her university notes just like me. She uses the inputenc package, since on her Windows that allows characters with diacritics such as è or ò to by correctly typesetted without having to type `e or `o instead. I don't use inputenc since on my Mac that generates "Keyboard character not set up for use with LaTeX" or something like that. So the first question is: why this difference? And the second question is: why does it happen that if she sends me a tex document I see √® instead of "è" and √≤ instead of "ò"? And finally, with pdfTeX that typesets to the original characters with diacritics: why? Shouldn't it typeset to what is typed as happens with XeTeX?