Private nameservers are your own DNS nameservers. They use your domain – such as ns1.yourdomainname.com and ns2.yourdomainname.com – instead of the name of your web hosting company.
The most common situation where private nameservers are used is by resellers who are trying to establish their own brand. Private nameservers not only look professional, they make the process of transferring between servers much easier. In the case of a transfer, you as the reseller, will not need to contact each of your clients – they will begin propagating to the new server as soon as you update your nameserver IP addresses.
If you would like to switch to private nameservers for your reseller account, please open a support ticket here: https://hostpapa.com/dashboard
Support ticket tips/info: https://www.hostpapa.de/knowledgebase/kb/how-to-open-and-access-support-tickets