A CDN serves your site from servers around the world, so it loads quickly everywhere.

1. Cloudflare (free): sign up and add your domain, then point your nameservers to Cloudflare (article 139). It instantly acts as a CDN and adds caching plus security.
2. WordPress: the Cloudflare plugin adds extra controls and one-click cache purging.
3. Configure caching rules in the CDN dashboard for static files (images, CSS, JS).

Tip: A CDN is especially valuable if you have visitors in different regions, or if your server is far from your main audience.