It often requires to do formatting in a worksheet and then apply the same in different worksheets of the workbook which is very time consuming activity. So here is the solution:-
If you need to format all the worksheets in a workbook the same way, first select the required worksheets using your mouse while holding Ctrl key Or with key combination of Ctrl + Shift + PageUp / PageDown key. Now that you have the worksheets selected, you can start doing the formatting and you will see the similar formatting has been applied in all the selected worksheets.
When you are done, click on any worksheet and you will come out of the selection of all worksheets.