You do not transfer, you install. If you cannot find a link to download the Mac version via your Adobe account online then you will need to download from the page linked below and then use your current serial number to activate it.
Be sure to follow the steps outlined in the Note: Very Important Instructions section on the download pages at this site and have cookies enabled in your browser or else the download will not work properly.
Photoshop/Premiere Elements 10:
http://prodesigntools.com/photoshop-elements-10-direct-download-links-pse-premiere-pre.html