How to uninstall Apache from MacOS

Question

I installed MAMP when I got my MacBook and then removed it form Applications folder after realising that MacOS comes with an Apache preinstalled. When I try to run index.php from the DocumentRoot, /Library/Documents/WebServer/, it only shows "It Works!", eventhough I deleted the index.html file.

I may be worng, but I'm guessing that it's probably because of the MAMP, which I removed from Applications earlier.

Is there a way by which I can know that if this is the problem or find what the problem is?

Thanks in advance.