Proxied sites are cached at the edge, so repeat visitors get pages from a location near them rather than from your server. The Performance & cache card controls that.
Clear cache
Changed something and still seeing the old version? Clear cache drops every cached copy for the zone. New requests fetch fresh content from the server and are cached again from there.
Development mode
While you are actively working on the site, turn Development mode on. Caching is bypassed for three hours so every change shows immediately, then it switches itself off. It is the better tool during a build than clearing the cache over and over.
Always Online
If your server stops answering, visitors are served the last cached copy of the page instead of an error. It covers a brief outage or a restart; it does not replace fixing the server, and pages that were never cached cannot be shown.
Early Hints
Lets browsers start fetching a page's stylesheets and scripts while the server is still preparing the page. Free speed for most sites; leave it on.
Tiered caching
Every zone gets smart tiered caching automatically. Edge locations fetch from a nearby tier instead of all going to your server, which raises the cache hit rate for visitors far from the server. There is nothing to configure.
Reading the numbers
The Traffic card shows requests, bandwidth, cache rate and threats blocked over the last 30 days. A low cache rate on a mostly static site usually means pages are sending headers that forbid caching, which is a setting on the site rather than here.