If you're running your own mail server, records to be created for success across the board include PTR, MX, SPF, and DKIM. You'll need to make your own DKIM key as well. I don't know your exact setup, not trying to confuse you but it is a bit detailed to run your own mail server.
Oh, you're using a 3rd party service. Setting up a PTR record depends on where you have the server located. If you have a VPS for digitalocean, for instance, setting the droplet to your domain name will automatically create the PTR record. If you have OVH, as an other example, you can set the PTR record from within their online manager console.
