In Excel, the default save format for workbooks is Exeel workbook (xlsx), which you can change manually if you want to save them in a different format, such as a macro-enabled workbook, Excel template, and so on:
First, the Excel2010 version operation method
Step one, the preferred Excel2010 File tab, and then click the Options button, as shown in the figure:
In step two, open the Excei Options dialog box, click the Save tab, and select the formatting options you want to save in the Save Workbook column of its interface, as shown in the picture:
Two, Excel2003 version operation method
Step one, select the Options command from the Tools menu, as shown in the figure:
Step two, and then select the 1-2-3 Help tab, select the default save format in the save Excel file as Drop-down list, as shown in the figure:
This saves the next time you save it in Excel by saving it to the file format you set up.