System Templates
System page settings apply to Hubspot accounts with the following plans only: Marketing Hub Professional, Marketing Hub Enterprise, CMS Hub Starter, CMS Hub Professional, CMS Hub Enterprise, and Legacy Marketing Hub Basic. Systems templates are used for certain types of pages generated automatically by HubSpot.
Customization
HubSpot does not offer drag-and-drop customization for systems pages. To customize systems page templates, you will need to directly edit the template. You can find the systems templates within the /templates folder.