GDPR compliance requires that you be reachable and responsive to user requests for data that you’ve collected on them either to view or delete.  You can create a simple consent withdrawal/request to view form on your Privacy Policy page. 

Use Joomla's Privacy component

Joomla 3.9 introduced the Privacy Component, which allows you to easily respond to user data requests and data removal. Contact Enhanced released a new Privacy plugin to add compatibility with this new component.

This plugin is included in Contact Enhanced PLUS and PRO version.