The LaTeX export back-end can insert any arbitrary LaTeX code, see Embedded LaTeX. There are three ways to embed such code in the Org file and they all use different quoting syntax.
Inserting in-line quoted with @ symbols:
Code embedded in-line @@latex:any arbitrary LaTeX code@@ in a paragraph.
Inserting as one or more keyword lines in the Org file:
#+LATEX: any arbitrary LaTeX code
Inserting as an export block in the Org file, where the back-end exports any code between begin and end markers:
#+BEGIN_EXPORT latex any arbitrary LaTeX code #+END_EXPORT