1: Open your bittorrent client. 2: Select File>New, or "Create new torrent", or whatever. 3: Pick the desired source file. 4: Create the torrent (and open it

1: Open your bittorrent client. 2: Select File>New, or "Create new torrent", or whatever. 3: Pick the desired source file. 4: Create the torrent (and open it and make sure the source file is in the destination folder if your client didn't do that on it's own (you want "download finished, seeding to 0 peers")). 5: Right click>copy magnet link, then paste into whereever. 6: Other person downloads the file just like with any other magnet link. It's obnoxiously unergonomic and rather slow (especially if your clients have to track down each other's IP addresses via DHT), but it's not actually hard.