Use Calibre to Convert Kindle Books You've Purchased to PDF

Calibre can be used to convert kindle books to PDF by installing a plugin called DeDRM_tools. You'll need the serial number of your Kindle device. As far as I know this only works with books you've purchased and if you own a Kindle.

1. Install Calibre v4.20.0
2. Download the latest release of DeDRM_tools v6.8.0 from their Github releases page
3. Open calibre's Preferences dialog
4. Click on the "Plugins" button
5. click on the button, "Load plugin from file"
6. Navigate to the unzipped DeDRM_tools folder
7. find the file DeDRM_plugin.zip
8. Click to select the file and select "Open"
9. Click "Yes" in the "Are you sure?" dialog box
10. Click the "OK" button in the "Success" dialog box
11. Enter your Kindle Device's serial number in the customisation dialog for eInk Kindle Books
12. Be sure to click OK and not Cancel
13. In your Kindle Content list, click the ... "actions" button for the book you want to convert
14. Click download & transfer to USB
15. Select the device that matches the serial number above
16. Drag the downloaded file onto Calibre
17. Click Convert books in Calibre
18. Choose the format you want and click OK

Now after a brief wait you'll have a PDF file that can be opened and annotated wherever you please.

I highly recommend PDF Expert and an iPad Pro w/ the Pencil 2.