vertico-posframe is an vertico extension, which lets vertico use posframe to show its candidate menu.
NOTE: vertico-posframe requires Emacs 26 and do not support mouse click.
(require 'vertico-posframe) (vertico-posframe-mode 1)
(setq vertico-posframe-parameters '((left-fringe . 8) (right-fringe . 8)))
By the way, User can set any parameters of vertico-posframe with the help of `vertico-posframe-parameters’.