When you embed your form into your website using the "iframe" tag, it may show a scrolling bar on your form. This is because the length of your form is bigger than the length of the iframe tag.
All you should do is to check your iframe code and find the "height=750" at its beginning. Then change the number 750 to something bigger, let's say, 1200. Save and refresh your page.
If it still has the scroll bar, you'll need to increase the height so it matches the height of your form. If it's too much and shows empty space under the form, decrease it to match the height of your form.