Sonaar use a custom post type to built the footer. 

So to edit the footer we have to go to wp-admin>headers & footers 

and edit the footer post used. 

All WPBakery page builder tools are available to built the footer as we want.

We can create more than one footer post. To select wich footer we want to use as default footer, we have to go to wp-admin>theme options>footer options

And select the footer post we want

We can also overwrite the default footer in each page settings