How to remove the empty spaces on the form embedded on my website?

and there are also some blank spaces in the back that I wish to eliminate

I'll place the screenshot you sent us on this thread for reference:

To remove that empty space surrounding your form, try injecting the following CSS Codes:

.form-all {

   width: 100%;

}

.jotform-form {

   padding: 0;

}

Here's where/how to inject them:

Complete guide: How-to-Inject-Custom-CSS-Codes 

If you're using V4, click the FORM DESIGNER icon on the right > CSS tab > then paste it on the INJECT CUSTOM CSS section.

RESULT: