Cloudflare is a cloud CDN or Content Delivery Network, this network distributes files across many servers all over the world, so that no matter where on earth you are, there's a server nearby with the files your requesting readily available.
A website is a collection of files that are hosted on a server and called as needed for each web page you visit.
There are many other factors involved too like DNS lookups, database queries, preprocessing scripts, "rendering", and "painting".
Cloudflare handles DNS lookups also, providing the fastest (according to third-party testing, at the time of writing this) name servers on the internet. So much so you can change your device to use Cloudflare's one dot DNS and see noticeable improvements.
Optimizing your website with Cloudflare is mostly painless, just follow these steps…
First signup for Cloudflare:
Next, add your presumably slow website, by entering the domain name:
Once added you will be presented with a splash page explaining what's going on in the background, just click next.
Select one of Cloudflare's excellent pricing plans…
Optimize your DNS records…
Here is where it gets technical, first Cloudflare is pretty accurate about grabbing all your DNS records but just too make sure you want to compare against your existing DNS hosting provider or registrar, which you can look up here:
Use this step to add in your Google Gsuite and Mailchimp DMARC, DKIM + SPF records.
Now it's time to update your nameservers: