First, you will need DeDRM v10.0.9 beta/RC or the alpha release. This will work on many (but not all) Kindle ebooks. (Some Kindle books come with extra-strength encryption that these tools cannot handle, etc.) If you have questions about installing, setting up, or using DeDRM, ask on GitHub.
“many but not all” hm.
I had some issues at first then decided to actually RTFM and once i entered my kindle serial number into the plugin, worked perfectly.
FWIW, I did not have a single book with DRM issues. That being said, I don’t have too many “hot bestsellers” or something similar.