In which section of the thesis should I give information about formatting? How? I am writing my Ph.D. thesis in mechatronics field. I used some notions from mechanical engineering and control engineering, but my work is mostly about a software solution. As the content is really multidisciplinary, it is possible that some of the readers do not know the even the basics of software-related practices. I want to inform them about the formatting of the text, for example an XML-element looks like &lt;element&gt;, or I have written a class name like Class. Where is the right place to do that? Introduction? And any examples how?
It is frequently the case that a scientific work will explicitly introduce its notational conventions to the reader.  Sometimes this is done inline, but if there is a significant amount to explain, it's nice to set it aside in an easily identifiable portion of the document with a name like "Notation."

If the conventions will be used throughout the thesis (as it sounds will be the case for you), then a good place to do this is following the introduction, either as a subsection or as its own chapter, depending on the size and complexity of what you write.