month - the month of the year (a one-digit or two-digit number; see note).
day - the day of the month (a one-digit or two-digit number; see note).
year - the year (four digits between 0001 and 4000. For example, 2014 but not 14).
The format of the result depends on the date format that was in use when the database file was created. In the United States, dates are generally in the format MM/DD/YYYY. You can change the date format in your operating system.
You can change how the date is displayed by assigning a different date format to the field in Layout mode. Changing the formatting in this way only affects the way the data is displayed, not how it is stored.
Date(13;1;2014) returns
1/1/2015 (one month after December 1, 2014).
Date(6;0;2014) returns
5/31/2014 (one day before June 1, 2014).
Date(6;-2;2014) returns
5/29/2014 (three days before June 1, 2014).