Tips on Customizing Kaya QR Code Generator

How to Hide Kaya QR Code Generator Admin Menus

function plt_hide_kaya_qr_code_generator_menus() {
	//Hide the "Kaya Studio" menu.
	remove_menu_page('kayastudio-plugins-admin-main-page');
	//Hide the "Kaya Studio → Kaya Studio" menu.
	remove_submenu_page('kayastudio-plugins-admin-main-page', 'kayastudio-plugins-admin-main-page');
	//Hide the "Kaya Studio → QR Code Generator" menu.
	remove_submenu_page('kayastudio-plugins-admin-main-page', 'wpkqcg-kaya-qr-code-generator-admin-settings-page');
}

add_action('admin_menu', 'plt_hide_kaya_qr_code_generator_menus', 11);

Where do I put this code?

How to Hide the "Kaya QR Code Generator" Meta Box

function plt_hide_kaya_qr_code_generator_metaboxes() {
	$screen = get_current_screen();
	if ( !$screen ) {
		return;
	}

	//Hide the "Kaya QR Code Generator" meta box.
	remove_meta_box('wpkqcg-page-meta-box-qrcodemetabox', $screen->id, 'normal');
}

add_action('add_meta_boxes', 'plt_hide_kaya_qr_code_generator_metaboxes', 20);