The put command has -delete switch that does this:
https://winscp.net/eng/docs/scriptcommand_put#delete

Hi,

I have a FTP in passive mode and port range restriction.
Sometime, my application hang to make the FTP because all port are used.

So, I analyse the idea to use winscp for copying generated reports to a folder and sync this folder with my web server.

I can schedule a call to an WinSCP script each hour and sync files with the remote server.
But my desire is: if the file has been successfully transferred, the file on local is deleted.

With this scenario, if the transfers failed the file are keep on local and ready for next run.