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 app/bundles/UserBundle/Views/Security/login.html.php
into themes/system/MauticUserBundle/Security/login.html.php
then make the desired changes.
Warning
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.