My notes on DNS

[shreshthmohan]

Checking the result of DNS settings for your domain

dig @8.8.8.8 +trace shreshth.dev

An apex domain is a custom domain without a subdomain, e.g. google.com.

Whereas a subdomain is what you prepend to your domain, e.g. in www.google.com, www is the subdomain

Usually, your apex domain (shreshth.dev) has to point to an IP address and cannot point to another domain address. So in your DNS settings, an A record will have to be pointed to the IP of your hosting provider's load balancer. (TODO: add note about ALIAS records available with some providers)
This site's A name record:

shreshth.dev.		3600	IN	A	76.76.21.21

Any other subdomains can point to both IP addresses and non-IP addresses, i.e. other subdomains. cat.example.com can point to www.catexample.com, or to 76.76.21.93.

This site's www subdomain CNAME record

www.shreshth.dev.	3600	IN	CNAME	next-blog-mu-three.vercel.app.

IN stands for internet

Julia Evans has a good article that helps you understand how a DNS lookup works.