InBox Placement is crucial
Sending domains can be used across multiple IP addresses and multiple email service providers. ISPs have adapted to weigh this piece of information the most heavily when deciding whether or not to trust your mail–essentially ISPs take the stance that you’re guilty until proven innocent.
They do this because businesses tend to want to have their emails look like they are coming from their website and, as a result, change their sending domain less than other elements of their sending infrastructure. It is crucial that you do not send to people who don’t engage with your emails because ISPs will believe that all email from your sending domain are not wanted, resulting in more of your emails landing in the spam or junk folder.
A From address is the reply-to email address you use for your campaigns. Not to be confused with a From Label, which is just the name that comes through as the sender when an email is received. For example, a campaign email might have the From Label as Mark | YourBrand, but the reply-to address is [email protected].