If you find that you keep applying the same formatting over and over, create a style with that formatting so you can apply those formatting settings with one click.
If you decide you need to change an existing style, you can easily make modifications. Any updates you make will automatically be reflected in any cells that have the style applied.
Click the Cell Styles button.
Right-click the cell style you want to modify.
Select Modify.
To duplicate a style before making changes, select Duplicate from the menu instead.
Click the Format button.
Select the formatting options you want to use.
Click OK.
Click OK again.
The style is updated and any cells with the style applied are automatically updated.
To remove a cell style from all cells and delete the cell style itself, click the Cell Styles button on the Home tab. Then right-click the style and select Delete.