Create an invisible field that appears only after answering another field

I wonder if there is such option.

In this my case, I would have a field. He would answer YES then automatically arise other field below.

Thanks!

Yes this is possible, you can use the conditional logic feature of the form builder to set actions with specific rules. Here's the guide that you can refer: http://www.jotform.com/help/57-Smart-Forms-Using-Conditional-Logic.

Do let us know if you need more information on this.

Thanks.