Can I edit the text in the text box?

Yes, I believe you are referring to this form: http://www.jotform.com/43136708438256

All you need to do is to go into the edit mode of the form:

1) Login to your account at www.jotform.com

2) Go to MY FORMS

3) Select your form and click on Edit form

4) Select your field, if it's the Text Field, simply click on "Edit HTML"

IF it's for your Heading fields, click on the gear icon and then on Show Properties

Also, if it's for the labels, you double click on the labels and you will be able to edit them.

Hope this helps, if you need anything else, please open a new thread, we will be glad to assist you.