Hi Kirti,
All dates in mendix are datetimes in the backend. You can convert this to a string by using formatDateTime, see Parse & Format Date Function Calls - Studio Pro 9 Guide | Mendix Documentation for documentation.
You can specify the format you want, e.g. formatDateTime($YourDate,'MM-dd-yyyy').
Note that if you are using it for displaying purposes in mendix, you can also choose the format in the properties where you show this attribute/text.
Hope this helps!
Mendix accepts Date time only.