A handy addition to our favourite Excel keyboard shortcuts: typing Control-; will insert the current date. If you want the current time, type Control-Shift-;.
As Helen Bradley's Project Woman site notes, Excel has functions for inserting the current date or time (=TODAY() and =NOW()), but those values regularly update whenever you recalculate the worksheet. The keyboard shortcuts are a nifty way of time or date-stamping specific cells.
Trevor’s Quick Excel Tip – Date and Time [Project Woman]