Hi...
If you wish to export without a background you can choose the Sequence Image PNG option in the Windows version or use the Apple ProRes 4444 codec in the Mac version.
If you are exporting a 2D Head be sure to go to File > Background Settings and choose "Actor Only". For both 2D Heads and 3D Heads you should not have any kind of background applied.
You can find more detailed instructions in the Online Manual > Exporting section
HERE.
Peter
Forum Administrator
www.reallusion.com