Done now, thanks to Tech and nmb.
But I agree with doktornotor.
So, to send files we have to use 7zip. Is there any such option for WinRar or WinZip or Power-Archiver or TugZip or PeaZip or ....
I think we need a tutorial section here about how to encrypt filename using .... utilities
I know there is option to send files through Virus Chest. But there are few persons like me who love Avast, recommend it to all but do not use it all time because of the habit of testing different AVs time to time.