Is there a way to insert a Date and Time element with a time-zone option?

My clients are all over the U.S., and when they submit their services forms to me, I'd like to know what time zone they're in. I don't see a Date and Time feature that allows that.

You can add a Timezone Picker widget:

http://widgets.jotform.com/widget/timezone_picker 

You can make the widget required so that your clients need to select the timezone in order to submit the form. You can test it here:

http://form.jotformpro.com/form/50506501135947 

Let us know if we can assist you further.