When you scroll to the bottom of your page you will see your footer area marked with 'Footer' and an arrow down indicating where the footer starts from. Everything that you add in the footer area will show on all pages that have the footer enabled.

You can drag and drop widgets into the footer area the same as you do with other blocks in the builder.

To hide the footer for the page, simply click on the Hide button for that page. This is great for sales pages where you want to limit the number of ways out of the funnel.