how to make the spreadsheet to have invisible cell

I'm not sure if someone asked the same question, but I couldn't find it.

I would like to know how can I make the spreadsheet to have invisible cell i.e.
all the cells dont have boxes around them.

thanks in advance.

Go to Tool/Option... On the View tab, uncheck the Gridlines box in the Window options section.

thanks a lot to both of you.
that's what i need =)