In a recent communication, Amazon has alerted Kindle users about significant changes set to take effect from next month. The notification pertains to the phasing out of support for sending MOBI (.mobi, .azw, .prc) files through the “Send to Kindle” feature, starting November 1, 2023. This change, as News18 pointed out, specifically impacts users attempting to send MOBI files via email and Kindle apps on iOS, Android, Windows, and Mac.
Yeah you have to send through email. I guess some people might want to do via usb, I find sending to email easier tbh.
The email service also converts the file to a kindle format. You can send pdf or even text, but it does not mean that kindle supports it, it’s still a conversion.