Hi,
You could remove the footer completely and then insert your own custom template.
1) in your theme's directly, create this file if it doesn't exist:
Magento_Theme/layout/default.xml
2) add the following code to default.xml:
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
<body>
<referenceContainer name="footer" remove="true">
</referenceContainer>
<referenceContainer name="footer-container">
<container name="myfooter" as="myfooter" label="Page Footer" htmlTag="div" htmlClass="footer content">
<block class="Magento\Framework\View\Element\Template" name="myfooter.block" template="Magento_Theme::html/myfooter.phtml" />
</container>
</referenceContainer>
</body>
</page>
Where "myfooter.phtml" is your custom template file located under Magento_Theme/templates/html within your theme's directory. If you're working with an existing default.xml file, you would just insert the code that is inside the body tag into the existing body tag, and not the whole thing.
3. Flush the cache.
Hope this helps!