domain alias

[mojamoi]

in cpanel how do we set subdomain, parked domain and addon domains.

How is the nameservers pointed

for a domain abc.com

to add a domain sew.abc.com do we need to regsiter sew.com and then what do we do?

 

[Infopro]

The documentation should be useful to you I believe:

Add a Subdomain - cPanel Documentation

to add a domain sew.abc.com do we need to regsiter sew.com

No. abc.com needs to be registered and pointed at your server via your Domain Name Registrar. sew.abc.com can be created from your cPanel, with a few clicks. See docs link above.