wpmu_signup_blog( string $domain, string $path, string $title, string $user, string $user_email, array $meta = array() )

function wpmu_signup_blog( $domain, $path, $title, $user, $user_email, $meta = array() )  {
	global $wpdb;

	$key = substr( md5( time() . wp_rand() . $domain ), 0, 16 );

	/**
	 * Filters the metadata for a site signup.
	 *
	 * The metadata will be serialized prior to storing it in the database.
	 *
	 * @since WP-4.8.0
	 *
	 * @param array  $meta       Signup meta data. Default empty array.
	 * @param string $domain     The requested domain.
	 * @param string $path       The requested path.
	 * @param string $title      The requested site title.
	 * @param string $user       The user's requested login name.
	 * @param string $user_email The user's email address.
	 * @param string $key        The user's activation key.
	 */
	$meta = apply_filters( 'signup_site_meta', $meta, $domain, $path, $title, $user, $user_email, $key );

	$wpdb->insert( $wpdb->signups, array(
		'domain' => $domain,
		'path' => $path,
		'title' => $title,
		'user_login' => $user,
		'user_email' => $user_email,
		'registered' => current_time('mysql', true),
		'activation_key' => $key,
		'meta' => serialize( $meta )
	) );

	/**
	 * Fires after site signup information has been written to the database.
	 *
	 * @since WP-4.4.0
	 *
	 * @param string $domain     The requested domain.
	 * @param string $path       The requested path.
	 * @param string $title      The requested site title.
	 * @param string $user       The user's requested login name.
	 * @param string $user_email The user's email address.
	 * @param string $key        The user's activation key.
	 * @param array  $meta       Signup meta data. By default, contains the requested privacy setting and lang_id.
	 */
	do_action( 'after_signup_site', $domain, $path, $title, $user, $user_email, $key, $meta );
}