The feature is called <a href="https://docs.joinpeertube.org/admin/following-instances#instances-redundancy" target="_blank">"server redundancy"</a> and caches your most popular videos to help serve additional viewers.
Enable <a target="_blank" rel="noopener noreferrer" href="https://docs.joinpeertube.org/admin/configuration#live-streaming">live streaming</a> for your instance
Read the <a target="_blank" rel="noopener noreferrer" href="https://docs.joinpeertube.org/maintain/configuration#scalability">scalability guide</a> if you plan to have many users or viewers
Enable or disable signup, <a target="_blank" rel="noopener noreferrer" href="https://docs.joinpeertube.org/admin/managing-users#registration-approval">approve manually new users</a> or set upload limits