Overriding core view templates
You can override any view’s template in Mautic by creating a
themes/system directory, copying the core template file into a corresponding directory and customizing the HTML.
For example, to customize the login page, copy
themes/system/MauticUserBundle/Security/login.html.php then make the desired changes.
Customizations may break Mautic updates core templates in future versions. It’s best practice to review and reconcile customizations with core templates after each upgrade.