I'm experimenting with reverse shell tcp. I managed to establish a connection, but my question is, how do I mantain a connection even after I close the multihandler? And when I'm using the target's command prompt, how do I send files to the target's computer using his command prompt?
Pedro,
The short answer is you can't.
In order to maintain a connection you need to install persistence on the victim machine. You will still have to reuse the multi/handler in order to receive a new connection.
In order to transfer files you need to use the meterpreter payload in order to upload and download files.
However, if you have powershell on your target machine you can run a powershell download that will fetch internet hosted resources for you.
Hope this helped.