You can remove some of the header stuff with the following.
// remove unncessary header info
function remove_header_info() {
remove_action('wp_head', 'rsd_link');
remove_action('wp_head', 'wlwmanifest_link');
remove_action('wp_head', 'wp_generator');
remove_action('wp_head', 'start_post_rel_link');
remove_action('wp_head', 'index_rel_link');
remove_action('wp_head', 'adjacent_posts_rel_link');
}
add_action('init', 'remove_header_info');
The default installation does not include stuff like meta keywords, so that is either a theme or plugin that you are using.