Hello,
PTR records are created by the IP provider.
Obtaining Your Net Block
Before setting up reverse DNS with us, you will need to inquire with your ISP that they are willing to delegate control over the net block they have assigned you to ZoneEdit. In addition, ask your ISP if they can provide you with a PTR record for your IP addresses, or, if not, if they will be able to delegate to ZoneEdit. Once you have this confirmed, you will need them to provide you with the net block itself.