how to increase size of page

I see from other answers that in order to get my submit button to show i need to change code to increase the size of the page.  With the new jot form I can't find the place to go to add new code.  How can I do this?

To increase the size of your form, you can adjust it from the From Designer. Please see the images below:

However, if you mean you want to get the iframe code of your form and adjust the width to add it to your Weebly website. Here's a guide on how to get the iFrame embed code :Getting the form iFrame code

Related guide: 

Adding a form to Weebly

Adding a form to your Weebly website

If you need further assistance, please let us know.
Regards