I am testing an email template / campaign with dynamic content for several of my content areas and CTAs. Can I also set up a snippet/dynamic content for my subject line and have it populate based upon the segment like I'm doing with the other content? If so can someone direct me to article how to?
Yes, you can but you can't use a snippet in a subject line.
On the right side of the email editor, you will find Subject. Right-click and you can make it dynamic for a segmentation by clicking "Segment By"