Just known this really interesting feature: send email to kindle email and then doc you send will be in your kindle!
Here’s the steps:
1. Login to your amazon account
2. Hover “account and list” and click “manage your content and device”
3. Go to setting and scroll down. You’ll find your kindle personal email.
4. Under “Approved Personal Document E-mail List” click “Add a new approved e-mail address”.
Kindle Personal Documents Service supports the following file types:
Kindle Format (.MOBI, .AZW)
Microsoft Word (.DOC, .DOCX)
HTML (.HTML, .HTM)
JPEG (.JPEG, .JPG)
If you want to know more information, visit here