I try that and it still did not work

"Bob Umlas, Excel MVP" wrote:

Right-click the border of the text box (while the workbook is unprotected),
select Size and Properties, on the Properties tab deselect Locked & Lock text.

"Nick" wrote:

When I add a text box in to excel and protect the sheet but still allow a
user to edit it they can not add more line with enter. So who can they add
more lines?