Saving Files in Excel
Work should be saved regularly, even though Excel will save automatically as per the settings in the backstage SAVE area which can be accessed via the FILE OPTIONS menu or ALT, F, T. The keyboard shortcut most commonly used for saving is CTRL, S. This command overwrites the last version of the file saved.
The safest system when working on critical work, especially when the file is large, is to save multiple versions using the SAVE AS command. Press Browse, and a window will open for you to select the place where you want to save your worksheet.
The shortcut F12 is the fastest way to access this dialogue box: