• Select File > Info.
• Select the Protect Workbook box and choose Encrypt with Password.
• Enter a password in the Password box, and then select OK.
• Confirm the password in the Reenter Password box, and then select OK.

Choose the Excel-styled cells from the list. Right-click the style that was just applied under Home > Cell Styles. To make the changes you wish, choose Modify > Format.

Select the cells with the Excel Style. Right-click the applied style in Home > Cell Styles. Select Modify > Format to change what you want.

Choose the Excel Style for the cells. In Home > Cell Styles, right-click the style you want to use. To alter what you want, go to Modify > Format.