I want to remove the Country and Phone number from a return address and move the Addressees address to the right a bit more. Can this be done? Thanks in advance!

Yes, this can be done.

Go to the Design menu
Click on new envelope
Click next
Select the "Use an existing layout or... "
Click Next
Click Next

Now you're free to add and remove anything you like. Though I'm not sure how the phone number got on there unless you already customized an envelope.