how to populate data field with current date

You can use our calculation widget to get this. Here's an example form: https://form.jotform.com/53485742835970.

Here's how you can add the calculation in the form:

https://www.jotform.com/help/259-How-to-perform-calculation-in-the-form

Note that you can also use DataString to get the textual representation of the selected date. 

You have to click ... button (More Math Functions) in order to add DateString. 

Let us know if you need further help with this method.

I'm sorry. But just in case you have a typo error for the "data". You can set the default "date" to current: