Custom Pages Tab
It personalizes the error and challenge pages that Cloudflare presents to your visitors.
There are several option under this and all option only works in pro version. Not even a single option is free here.
1) IP/Country Block - Pro Plan
2) WAF Block - Pro Plan
3) 500 Class Errors - Pro Plan
4) Enable Origin Error Pages - Enterprise Plan
5) 1000 Class Errors - Pro Plan
6) Always Online™ Error - Pro Plan
7) Basic Security Challenge - Pro Plan
8) WAF Challenge - Pro Plan
9) Country Challenge - Pro Plan
10) I'm Under Attack Mode™ Challenge - Pro Plan
11) 429 errors - Pro Plan
For example - Let us suppose we want to customize the I'm Under Attack Mode™ Challenge page.
Default Preview of this page
So in order to customize it and change the look of this page -
Design a custom HTML page, then host it online (it may be hosted anywhere). Once you publish your custom page, Cloudflare will use our customized page instead of serving our standard default page.
We can preview our customized page as it will appear to our visitors before publishing.
Note: Once we add the URL and click “Publish”, Cloudflare will store our custom page on its servers. We do not need to host our custom page after it has been published.
I created a HTML page and then published it and then deleted the page from our server and now it is hosted on cloudflare. We can use default page or our designed page whatever we like.
Basic customized page created -
Video making things more easier to understand.