You can use the add_user_to_blog function after creating the user.
$userid = 1;
$blogid = 5;
$role="administrator";
add_user_to_blog( $blogid, $userid, $role );
You can use the add_user_to_blog function after creating the user.
$userid = 1;
$blogid = 5;
$role="administrator";
add_user_to_blog( $blogid, $userid, $role );