SELECT TO_DATE('14/07/2021','DD/MM/YYYY') FROM DUAL;

                                  WATCH OUT! 
/*      in the example before if you write '14072021' instead of '14/07/2021'
      you'll get the same result, if you want an exception to be thrown you    
      should add the prefix 'fx' (force) to the format, so that he will 
      match only the exact format. here's some examples:
         SELECT TO_DATE('14/07/2021','fxDD/MM/YYYY') FROM DUAL;--WORKS
         SELECT TO_DATE('14072021','DD/MM/YYYY') FROM DUAL;    --WORKS
         SELECT TO_DATE('14072021','fxDD/MM/YYYY') FROM DUAL;--EXCEPTION      */