The answer by @mpettigr is mostly correct, the given lines will satisfy flycheck for the file header (except that flycheck expects a newline after Commentary:).
Especially if you start a new elisp file, you could also use the header snippet for the yasnippet template package, instead of choosing Emacs-Lisp> Check Documentation Strings from the menu. This snippet expands to the following code to which also adds the required last line ;;; foo.el ends here to your file:
;;; foo.el --- Some summary -*- lexical-binding: t -*-;; Author: quazgar;; Maintainer: quazgar;; Version: version;; Package-Requires: (dependencies);; Homepage: homepage;; Keywords: keywords;; This file is not part of GNU Emacs;; This file is free software; you can redistribute it and/or modify;; it under the terms of the GNU General Public License as published by;; the Free Software Foundation; either version 3, or (at your option);; any later version.;; This program is distributed in the hope that it will be useful,;; but WITHOUT ANY WARRANTY; without even the implied warranty of;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the;; GNU General Public License for more details.;; For a full copy of the GNU General Public License;; see <http://www.gnu.org/licenses/>.;;; Commentary:;; My commentary;;; Code:(message "Hello World!")(provide 'foo);;; foo.el ends here