How to Hide Footer on a page

Do you mean the white row with Designed by in it? If so, try:
footer#footer .colophon {display:none;}

No,

I mean footer widget area 1,2 and 3…

How should I do that?

try:
.footer-widgets {display:none;}

it works on every page on my site.

How can I do this on 1 specific page on my site only?

.page-id-nn .footer-widgets {display:none;}.

Inspect the HTML and you’ll find the .page-id-nn on the body tag.
Can use .home .post if appropriate.

I can see on your site you solved, could you mark this topic as resolved?
Thank you.

thanks !!