There are good options to send files to other users directly, or P2P, and one of them is iSendr, who today becomes even more useful, cross-platform with support for sending multiple files at Android phones through QR codes.
The operation of this feature is very simple and only requires that we start a session from the desktop in the usual manner, after which the download link also obtain the QR code that can send or save to start the download when you want, from any Android phone.
All without the need to register, and also for free. In theory, this support should also work for iPhone as Apple's smartphone supports QR codes, but the problem is that the iPhone does not support Flash and it is this platform that is based iSendr.