If you are using any wordpress theme, there are no more option make on footer mulptile columns and rows, so you can take up new fresh wordpress page and create custom designs on page as required your client.
When your wordpress custom footer design will be finished, then save your custom footer template wordpress page and do publish for website visitors. after then wp page will be published, See on your web browser url path, you will get there automatic generated on unique Page Id, exp:"834".
How To Make Custom Footer Template For WordPress Site
WordPress Page ID Using Create Custom Footer Template
After that connect your ftp or cpanal to open your main footer.php there on wp theme, giving you below small wp code, keep on footer.php. and change your wordpress unique "page id" you did created on custom footer page link.See below wordpress code build for custom footer using wordpress page, and do copy wp code then paste on footer.php on bottom and then do only replace your page id, and do hide your old footer design.
I hope it's simple tricks you liked, if you liked this, please share your wordpress designer and developer friends circle.