how to make form bigger

Once on the edit mode of your form:

1) Go to Preferences

2) Form Style

3) Form Width

There you can increase the number to make it wider:

If you need to increase the width and height of your fields, you can do it using the Form Designer:

1) Click on Designer:

2) Click on one of your fields, and the Text Box fields option will appear:

Here are some guides that may be of your interest: http://www.jotform.com/help/300-Form-Designer-Tutorial-Let-s-create-fantastic-forms-

Let us know if you need more help, we will be glad to assist you.