So I've done plenty of APA papers, but I have never done one with two authors, so I came here since it's the fastest source for information, in my opinion. I would like to know or see an example of how to present both authors on the cover page.
I think things vary based on whether affiliations are the same or different for the two authors. I.e., if they share an affiliation, then you'd put them on the same line, but if they have different affiliations, then you put them on different lines with their affiliation below each.
It's also worth noting that I've seen quite a bit of variation in exactly how the title page is presented (e.g., numbered footnote for affiliations versus text at bottom of page). Journals seem to be able to work it out as long as what you provide is unambiguous.
Here's an example of an APA cover page with two authors from my own work:
According to the APA 6th Edition, you list all the authors in order of contribution, or in alphabetical order if their contribution is equal. They should be on the same line unless it does not fit.
Jane Smith and John Doe