;; Default latex export behaviour is 
;; \item {\bfseries\sffamily TODO} TITLE TEXT \hfill{}\textsc{TAGS}
;; 
;; Change to 
;; \item {\bfseries\sffamily TODO} TITLE TEXT \marginpar{\textsc{TAGS}}


(defun my-org-latex-format-headline-function (todo todo-type priority text tags _info)
  "Custom function to format headlines for LaTeX export."
  (concat
   ;; Add the TODO keyword with a different formatting
   (and todo (format "{\%s} " todo))
   ;; Add the priority if present
   (and priority (when priority (format "\\hspace{0.2em}\\%c" priority)))
   ;; Add the headline text
   (format "%s" text)
   ;; Add tags if present
   (and tags (format " \\marginpar\\textsc{%s}" tags))))

(setq org-latex-format-headline-function #'my-org-latex-format-headline-function)