Save a Workbook:
After you create a workbook in Excel and make changes to it, you can save the document to preserve your work. When you edit a workbook, Excel stores the changes in your computer’s memory, which is erased each time you shut down your computer. Saving the document preserves your changes on your computer’s hard drive, so to avoid losing your work, you should save a workbook as often as is practical.
Open a Workbook:
To view or make changes to an Excel workbook that you have saved in the past, you can open the workbook in Excel. If you have used the workbook recently, you can save time by opening the workbook from Excel’s Recent menu, which displays the most recent files you worked with in Excel.