For quick and easy file transfers, LocalSend is the plugin you want. It enables sending and receiving files directly between your e-reader and any other device (phone, computer, etc.) using the LocalSend protocol, all over your local network and without needing an internet connection. You can send current books, any file, and even route files to different directories by type. The plugin is MIT licensed and works with several popular e-reader models, including Kindle Paperwhite 10-12th Gen, Kindle Scribe, Kobo Clara/Forma/Libra Colour, and more.

If you use Calibre on your computer to manage your ebook library, this plugin is non-negotiable. It turns your e-reader into a wireless Calibre device.