1. Select the entire sheet
All cells in an Excel worksheet are locked by default. Click the small triangle between A and 1 in the top-left corner to highlight every cell in the worksheet.
2. Open the Format Cells men
Right-click anywhere in your selected area and choose Format Cells from the dropdown menu.
3. Uncheck the Locked option
In the Format Cells window, go to the Protection tab and uncheck the Locked box.
4. Confirm the unlock setting
Click the OK button to apply the change and unlock all cells in the worksheet.
5. Select a column to keep locked
Click the column header containing data you want to protect, such as formulas or calculations, to highlight it.
6. Reopen Format Cells for the selected column
Right-click the selected column and choose Format Cells again from the menu.
7. Unlock the sheet
In the Protection tab, un-check the Locked box to unlock it, then click the OK button to finish unlocking your Excel sheet.