OnionShare lets you securely and anonymously share files of any size. It works by starting a web server, making it accessible as a Tor hidden service, and generating an unguessable URL to access and download files. It doesn't require setting up a server on the internet somewhere or using a third party file sharing service. You host files on your own computer and use a Tor hidden service to make it temporarily accessible over the internet. The other user just needs to use Tor Browser to download a file from you.