I am really a novice in network terminologies.
Can you let me know how to identify if my existing website DNS is A-Record or CNAME? I have access to the web-server, so I will be able to verify the configuration settings.
The webserver has nothing to do with DNS, they are two totally separate systems.
The easiest way to tell is using nslookup, dig, or a website that does it for you.
Here is a link to a website, type the name in, the resulting report will tell say if it's a C-NAME or A Record.