To gain access to the site during its delegation, you just need to write an entry in the hosts file that looks like this:
1.2.3.4 example.com
where,
example.com is your domain.
1.2.3.4 - ip-address of your hosting server.
To find out what IP address is assigned to your site on cPanel, pay attention to the "GENERAL INFO" block on the right in cPanel:
The Shared IP Address column shows the IP address used by your sites.
You can find the hosts file on your personal computer in the following ways:
Windows XP/2003/Vista/7/10: WINDOWS\system32\drivers\etc\hosts
Windows NT/2000: WINNT\system32\drivers\etc\hosts
Windows 95/98/ME: WINDOWS\hosts
Mac OS X 10.2+: /private/etc/hosts
Linux: /etc/hosts
After these changes, you will be able to work with your site at example.com even before its DNS records are updated by providers (this process takes from 24 to 72 hours).
If necessary, do not forget to remove the entry from the hosts file.
