Serve PHP Website on another machine when using Mail in a box

I have a domain name - domain.io. I gave my box name - mail.domain.io
I am using digitalocean and my nameservers are pointing to ns1.digitalocean.com, ns2.digital...etc.
I am using A record for mail.domain.io to point to this machine where i installed mail in a box.
Problem is, I want to serve a wordpress website on domain.io from another machine, which is already setup.
Can anyone please help me here and suggest me how i can do that…

For the domain in question, just make a new A recorder pointing to the server hosting the site.