I am new to managing websites and just set up a personal website for myself.
I had like to replace
404 Not Found Error page, in the same way many websites do it.
How do I go about it?
Create a file with the name .htaccess put it in the root of your website and inside that file write:
ErrorDocument 404 /notfound.html
Instead of /notfound.html write the path to your 404 page.
you can found here how to do what you want with Apache HTTPD: