To apply a cell style, navigate to the cell that you want to format. Alternatively, you can select multiple cells to change their formatting together.
Then proceed as follows:
Applying directly via the dropdown menu of the icon
If you click on the Cell styles 
icon on the ribbon tab Home | group Format, the program opens a dropdown menu with various predefined styles (and custom styles if created). Here, you can directly select and apply a suitable cell style.
Further down in this dropdown menu, you can use the option Styles in use to display the styles already used in the current document by enabling the checkbox.
For advanced options, click on the entry Manage cell styles in this dropdown menu to open the dialog box (see below and the following pages).
Advanced options: Via the dialog box
| 1. | On the ribbon tab Home | group Format, click on the Cell styles icon and select Manage cell styles in the dropdown menu. |
| The program displays a dialog box with a list of all cell styles. |
| Tip: You can use the option Show to determine whether all available styles should be displayed in the list – or only those already used in the current document. |
| 3. | Select the desired cell style in the Styles list. |
| 4. | Click on Apply. |
The formatting of the selected cells immediately changes to that which you specified in the cell style.
To clarify, a cell style can include the following formatting options:
▪Number format
▪Font (font and font size, text styles, etc.)
▪Cell alignment
▪Shading
▪Borders
▪Cell protection
In the section Format includes of the above dialog box, you can (optionally) specify exactly which of these formatting options should be used when you apply the selected cell style (see also next section).