How to make new Sub-domain?

My Nameservers’ point to Cloudflare,
then how can I make a new sub-domain?

Create the subdomain in the control panel, then add the DNS record to Cloudflare to point it to your website IP.

What do you mean?
Aren’t you able to create one from cPanel?

@Admin,
What’s my website’s IP.

And If I create DNS record there, will I able to install software thorugh Softaculous?

@DhananjayS said:
@Admin,
What’s my website’s IP.

The same as the IP address already configured for your root domain?

@DhananjayS said:
And If I create DNS record there, will I able to install software thorugh Softaculous?

You can use Softaculous completely regardless of your DNS status. Your DNS settings can be completely messed up and the domain been seized by the government and you can still use Softaculous as long as the domain is still assigned to the account.

Thanks!