Setting up custom error page on cloudflare

Hi Team,

I wanted to set up a custom page on the website. I am using ::CLOUDFLARE_ERROR_1000S_BOX:: error token as of now.

The custom page url is www.helloworld.com/splashpage.html

My question is,
lets say, if someone types in the url www.helloworld.com/goodmorning.html and cloudlfare returns 1020 error code, what will happen?

  1. will the browser url change to custom page url ?

  2. if answer to above question is yes, is there a way to keep the requested url as is and only show the contents from custom page?

Please let me know if my question is unclear.

Thank you.