Now make the book your reading, your kindle lock screen image, finally! First
spotted by Engadet, the most awaited feature was previously available after
jailbreaking the device. Now the long overdue feature of Display Cover is over
and Amazon claims that it works with most magazines, books and manga.

Source: see.mashable.com But the feature is only limited to certain kindle
device, Kindle (8th, 10th generation), Kindle Paperwhite (7th, 10th gen), Kindle
Oasis (8th, 9th, 10th gen), and Kindle Voyage (7th gen).

Many people on redditkindle have given suggestions on how promotions on
ad-supported can be disabled; either by paying $20 or asking real nicely to
customer support requesting for it to be disabled.

You can activate your display cover feature by going into Device
options>Setting>Show cover options>Display cover, turn on the toggle. But make
sure that your reading material isn’t mmhhhh? mmhhhh?