For many authors, the main output of their work will be the PDF report, in which case they can utilize the powerful styling of LaTeX. In this chapter, we discuss approaches that can be used to customize PDF reports, such as including LaTeX code or packages in the preamble, using custom LaTeX templates, adding headers and footers, generating sub-figures, and writing raw LaTeX code in the document body.
We want to offer a note of caution before we start, however. One benefit of R Markdown is the fact that a single source document can create documents with multiple formats. By tailoring your work to a single output format, you may improve the appearance and performance of a single output format but at the expense of this transferability. This problem is not unique to LaTeX, but all other output formats.