What is a PTR record and how to add one?
While the main purpose of the Domain Name System is to point domains to IP addresses, a PTR record works in the opposite way - it associates an IP with a domain name. Because of its purpose, a PTR record is sometimes called Reverse DNS Record. The purpose of a PTR record is mostly administrative - it shows an IP is in fact used with a particular domain.
SiteGround provides PTR records only for Cloud or Dedicated server owners. The IP addresses used on a Cloud or a Dedicated server are reserved for that particular server, and since you will be the sole occupant, they can be linked to your domains. One PTR record can be configured per IP, linking that IP to a single domain.