When you protect a worksheet, all cells are locked by default. This means that users cannot insert or delete rows. However, you can specify which cells users are allowed to modify.
To allow users to insert or delete rows:
(Optional): To prevent users from accidentally modifying locked cells, you can display a warning message or a notification.
(Recommended): To display a warning message that reminds users they are changing a locked cell, under Cell Error Alerts, click Warning. In the Title box, type a title for the message box, and then click OK.
(Not recommended): To display a notification that tells users they are changing a locked cell without saving their changes, under Cell Error Alerts, click Information. In the Title box, type a title for the message box, and then click OK.