I have been given the task of figuring out how to send emails from a different domain. As an example, lets say my company's domain is 'abc.com'. I'm looking to send emails on our clients behalf. Let's say the client's domain is 'xyz.com'. The IT staff at xyz.com are ready and able to help however they can. We have a lot of clients, so I imagine the steps might be different for different clients, depending on the what technologies they use.
What steps do we need to take to send emails on our client's behalf? What steps do our clients need to take to allow our emails to send correctly.
There seems to be DNS, SPF, and DKIM issues.
From what I can tell, no one on the internet has created a comprehensive guide for this.
Might someone be able to assist?