To add a header, in Page Layout view, click in the "Click to add header" area. The Header & Footer Tools and the Design tab appear at the top of the Ribbon.
As a finishing touch, suppose you decide to add headers and footers to the worksheet, to make it clear to everyone what the data is about.
First, change to Page Layout view. Click the View tab, and then click Page Layout View in the Workbook Views group. (Or click the middle button on the View toolbar at the bottom of the window.)
It is very easy to add headers and footers in Page Layout view. Instead of opening a dialog box to add a header, just click in the area at the top of the page that says Click to add header.
As soon as you do, the Header & Footer Tools and the Design tab appear on the Ribbon. These have all the commands to work with headers and footers. There's also a command, new in Excel 2007, to apply different headers and footers on odd and even pages.
For the header on this report, you type June Sales Report, and you're done. As soon as you click the worksheet, the Header & Footer Tools and the Design tab and commands go away, until you need them again. To get them back, in Page Layout view, click in the header or footer area again.
You'll see how to work with headers and footers in the practice.