Create a global variable for use in all templates

You’ll also have to fill the variable, e.g.

function userinfo_global() {
    global $users_info;
    $users_info = wp_get_current_user();
}
add_action( 'init', 'userinfo_global' );

And you should then be able to use $users_info everywhere in global context. Keep in mind that some template pars (header.php, footer.php, those used via get_template_part) are not in global scope by default, so you’ll have to use global $users_info; in those files before accessing the variable.