1. For example, if you want to find the book "The Old Man and the Sea" in txt format, you should first open Google, then type "The Old Man and the Sea filetype:txt" in the search box, and finally you can search out many related resources.

2. You can also find it on Baidu cloud disk, for example, find an e-book of the old man and the sea in mobi format, or open Google, and then enter the "MobiSite of the old man and the sea: pan.baidu.com/s/"in "search box, and all the files related to MOBI of the old man and the sea on Baidu cloud disk will be found.

Second, go to the kindle sharing community and look for it on the platform.

1. official website and Amazon officially recommend many free e-books. For example, if you open the official website, you will see the free column.

2. In many kindle e-book forums, there are many book lovers sharing their e-books. It must be very rewarding to visit such forums more often.