Could you please tell me is it possible to export CATIA V5 file to the lower release of this product?
For example form 2014 to V20.
Yes, it is possible with the Downward Compatibility program. However, the history will be lost.
try saving it as .STEP file, and open it on V20
As Jasper said, quickest and easiest is File > Save As > STEP.
You can learn more about STEP files here: