I want to adjust my form to fit a my mobile website in muse.

To make your forms mobile responsive, simply follow this guide: How to make Forms Mobile Responsive

You can also check out our Mobile Responsive widget to make your form responsive: http://widgets.jotform.com/widget/mobile_responsive 

To add a widget, you can check out this guide: How to Add a Widget to your Form

Do let us know if you need further assistance.