You may see 'my own store' pop up in places on book-pages on my website. Yes, I'm trying to help people who want to avoid buying from the big tech bro places like Google, Amazon, etc.
The books here are available as 'epub' format files, which won't work natively on Kindle devices, but there is a trick for that. Your Kindle has its own email address. You can find that in your account under devices.
Click that option, find the Kindle you want to send the book to (one of the many Kindles you own, no doubt!) and then, in the details, you can find the email address where to send the epub file:
You do need to make sure that Amazon recognises your sending email address as a valid one, otherwise the sending will be rejected. Find out how to set this up via this Amazon help page.
Additional note: my own store only allows for Paypal payments, unfortunately.