I just bought adobe photoshop elements and it's a windows version.  How do I change my order to a mac version?

A reasonable first step would be to post in the right forum.  We don't do Elements here.

Here's the link to the forum you want:

Photoshop Elements

As for the Chat thing:

Unfortunately, only Adobe customer service can assist you with your issue. These are user forums; you are not addressing Adobe here.

Click on the link below, and after that click on "Still need Help? Contact us."

Then on the next page, click Chat

There is also a phone option.

http://helpx.adobe.com/contact.html?step=PHXS_downloading-installing-setting-up_licensing- activation

Finally,

Phone support | Orders, returns exchanges