Unlike common word processors such as Microsoft Word or LibreOffice Writer, LaTeX usually does not provide WYSIWYG (‘What You See Is What You Get’). With LaTeX one takes plain text and enriches it with markup. This markup tells LaTeX about the logical meaning of certain elements of the text, similar to the way HTML does.
Take for example the element <h2> indicating a new section in an HTML document.
LaTeX also has a command for this; here one would use the \section command.
Because LaTeX files are not the document itself but rather instructions
on what each part of the document should be, you don’t normally give other
people your LaTeX file itself. Instead, after writing your LaTeX source, you
run LaTeX on the file (normally using a program called pdflatex) to
create a PDF file. This PDF is then what you send to others.
Different people use different ways to describe this process. As using LaTeX is a bit like programming, it’s often called ‘compiling’ your document, although ‘typesetting’ is more accurate.
For simple files, you only need to typeset your file once to get the completed PDF. But once you start adding more complicated things, like cross-references, citations, figures, and tables of contents, you might need to run LaTeX more than once. We’ll tell you when that’s the case.
In the next lesson, we are going to see that LaTeX is not a single program. To keep things simple, we are going to focus on one particular LaTeX program, pdfLaTeX, for creating your PDFs. We will look at some other programs, and why you might want to use them, later in the course.