What mechanism Winscp is using while creating and deleting files

I was expecting that winscp is using 'rm' command to remove files like we use it while deleting files from putty.

I have done some changes at the OS level due to which my OS user "applftp" is unable to delete any file from putty and once i connected through winscp using same user, it can delete the file.

WinSCP uses commands of the protocol your are connected with (SFTP, FTP, etc). How's that implemented depends on the server. But I'm pretty sure that no server launches shell commands for that.

Thanks for your reply.

Can you please how can i restrict OS user to only create and rename files only using Winscp and must not be able to delete files even created by itself.

Again, that's not a question for WinSCP. That's about the server you are using.