Přechod z Windows na MAC

If you only purchased a Windows version, you will not be able to switch to a Mac.  Some versions will be sold as a dual platform. 

It sounds like you have already discovered that you only purchased the Windows version.  But to confirm whether this is true, go to the Products page of your Adobe account.  If you click on the Download link, you will see if a Mac version is available for your account.  It will look like this:

If you do not have a Mac version, you can try contacting Adobe Support to see if they will allow you to switch.  Otherwise, you will have to buy a new version of Elements.