Sometimes when your top domain is already used with a mail service like gmail.com or fastmail.com but you would like to have some kind of email forwarding, you can use a subdomain for that purpose.
The process is exactly like with a normal domain. First step is you add the sub domain into our dashboard. The next step is configuring DNS record: MX and SPF. But at the place where you leave empty or using
@ you would now enter the sub domain.
Let's walk through a use case where we want to forward email to domain
qa.8moon.xyz so that
email@example.com can be forwarded to your own
QA team email. You just need to follow the same steps to set MX and SPF records. However, where you leave the hostname empty or use `@` on your domain registrar, you will enter `qa` now. Take namecheap.com as an example, here is how the DNS looks like.