We all are aware about today() and now() formulas which insert current date and current date/timestamp. But these change with every recalculation of your worksheet.
But if you want to enter the current date and time which doesn't change with recalculation i.e. it gets fixed, then following Excel shortcuts can be used.
Current Date – CTRL+:
Current Time – CTRL+SHIFT+:
Current Date & Time – To insert the current date and time, press CTRL+; (semi-colon), then press SPACE, and then press CTRL+SHIFT+; (semi-colon).