PTR or reverse DNS can only setup by the ISP who owns the IP address. You should contact your ISP to setup the PTR recocord for your IP.
Each IP block is assigned to dedicated name servers. Your IP belongs to your ISP and the reversed lookup will go to your ISP's name servers to resolve. Therefore, you can only ask your ISP to setup the reverse DNS for your IP.
Reverse DNS will affect the delivery rate for email servers. For an email server without reverse DNS lookup, emails sent through the server won't reach a lot of email addresses. Most email server has reverse lookup to check the credential of the server and will reject your email if your server does not have reverse lookup.
If you can not have reverse DNS setup for your IP and still want to run a email server, the only solution is to sign up our mail relay outbound service and use our mail relay server as smarthost gateway for your email server.