DateString

DateString[] gives a string representing the complete current local date and time. 

DateString[date] gives a string corresponding to the given date specification.

DateString[{"elem1","elem2",…}] concatenates the specified elements in the order given.

DateString[date,fmt] gives elements specified by the date format fmt for the date or time specification date.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.