[eftepede]

Note: nowadays EPUB is a 'kindle friendly format'. Amazon promised to ditch .mobi support (when sending as e-mail or using Send To Kindle apps) on August. They still work (you will have an e-mail with a warning 'in August 2022 it will be gone', lol), but people are encouraged to use EPUB.

I assume there is some conversion from EPUB to 'new mobi' (azw3 maybe, I forgot the name), but it's on Amazon's side. I've sent 20+ EPUBs via e-mail to my Kindle in the last two months and all of them work like a charm, no problems with formatting and stuff.