Footer styles are coming through ‘Elementor’ and you can edit those styles from ‘Template > Saved Templates’.

Those templates which are assigned under ‘Custom Footer’ category are the templates of footer. You can edit all those templates through ‘Elementor’.

You can add new templates for footer from ‘Templates > Add New’ (Choose ‘Section’ as template type, name your template and click on the ‘CREATE TEMPLATE button).

After creating the template, please choose the ‘Custom Footer’ category for that template.