I suspect most individuals use online control-panels, from their domain-registrars.<p>If you need to be dynamic, or outsource your DNS, there are options from Dynn, Digital Ocean, Amazon, etc, which allow you to use their API (and optionally a panel-interface).<p>Those APIs can be wired up to allow you to update things frequently if you wish, for example automating zone-transfers from a hidden-master, or converting a git-repository of text-files into live DNS entries.<p>Really your question is quite broad, and a more specific question would be required to provide a decent reply.