Note : There can be two types of password protection, one to open the
document and the other to edit the document. The following solution will
only work if the document is not password protected for editing.
Display all hidden rows and columns at the same time
To select all cells on a worksheet, do one of the following:
Click the Select All button.
Select All button
Press CTRL+A.
Note If the worksheet contains data and the active cell is above or to the
right of the data, pressing CTRL+A selects the current region. Pressing
CTRL+A a second time selects the entire worksheet.
On the Home tab, in the Cells group, click Format.
Excel Ribbon Image
Do one of the following:
Under Visibility, point to Hide & Unhide, and then click
Unhide Rows or Unhide Columns.
Under Cell Size, click Row Height or Column Width, and then
type the value that you want in the Row Height or Column Width box.