How can I removed the border around the form

how can i remove that border around the form?

http://m2p.417.myftpupload.com/

You must be referring to the box-shadow border around the form.

Please add this CSS codes on your form 

.supernova .form-all, .form-all {

    box-shadow: none !important;

}

result:

Let us know if this did not work.

also, i selected the rectangle form from the advanced designer layout and its displaying my form field with rounded corners.

HOw can i make this form field box a rectangle? and is it possible to make this form field taller in height? 

I can see that it is already rectangle. Both form embedded and on the direct URL/Link is showing with Rectangle corners.

If you are still seeing them as Rounded, please try clearing your Browser's Cache http://www.refreshyourcache.com/en/home/. I have cleared your Form Cache for now.