The sheet names that Excel 2010 uses for the tabs in a workbook (Sheet1 through Sheet3) are not very descriptive. Luckily, you can easily rename a worksheet tab to whatever helps you remember what the worksheet contains, provided that this descriptive name is no longer than 31 characters.
Select the sheet whose tab you want to rename.
The selected worksheet is active and the current sheet name appears in bold letters.
Double-click the sheet tab.
You also can right-click the sheet tab and select Rename on its shortcut menu. The current name on the sheet tab appears selected.
Replace the current name on the sheet tab by typing a new sheet name.
When you begin typing a new name, the previous name disappears.
Press Enter.
Excel displays the new sheet name on its tab at the bottom of the workbook window.