When assigning a domain or subdomain to a folder on your webspace, Varnish Cache is enabled by default for that domain or subdomain. You have the option to disable Varnish Cache for your entire account by navigating to [Webhosting] in the Control Panel, then going to [Webserver Settings] and clicking on [Manage] under Varnish.
There, you can set the cache time to 0 and clear the cache. If you only want to cache certain domains or subdomains with Varnish, you can leave the global cache disabled and enable the cache for the specific site in the advanced subdomain settings.
This setting can be found under [My Hosting], then go to [Subdomains] and click the [Edit icon] for the respective [Subdomain].