i had my domain purchased in namecheap and dns records there are pointed to DigitalOcean(DO).

Now i added a DNS for test.com(non www version ) in my DO panel.

I am using nginx server and also made changes in the file
server_name test.com www.test.com;

Now Is it necessary to add other DNS for www.test.com(www version) in DO panel.

because when i go to link test.com it’s working fine but when i go to link www.test.com chrome giving me this error

The server at www.test.com can’t be found, because the DNS lookup failed. DNS is the network service that translates a website’s name to its Internet address. This error is most often caused by having no connection to the Internet or a misconfigured network. It can also be caused by an unresponsive DNS server or a firewall preventing Google Chrome from accessing the network.