Sideloading

Here are Amazon’s instructions https://www.amazon.com/gp/sendtokindle/ 

From your browser

Send news articles, blogs posts and other web content to read them anytime, everywhere on Kindle devices or reading apps.

Send to Kindle for Google Chrome
Send to Kindle for Mozilla Firefox

From your desktop

Send your personal and business documents to read them anytime, everywhere on Kindle devices and reading apps.

Send to Kindle for PC
Send to Kindle for Mac

 

From your e-mail

Attach and send your documents to Kindle using the “Send-to-Kindle E-mail Address” to read them anytime, everywhere on Kindle devices and reading apps.

Send to Kindle by E-mail

From your Android device

Send documents from your Android phone or tablet to read anytime, everywhere on your Kindle devices and reading apps.

Send to Kindle for Android