The folder of the e-book on the phone was hidden, and I couldn't see how to deal with it on the phone.

If the folder of your phone's e-book is hidden in your phone and you can't see it, you can try the following methods: 1 Use the "file manager" function of your phone to open the folder where the e-book folder is located. If the folder was inside the phone, it would usually be found in the "file manager" or "explorer" of the phone. 2 Find the folder and click on the "Show all files and folder" option to view all the files and sub-folder in the folder. If the files and sub-folder in the folder are empty, then the folder itself may be hidden. In this case, you can try to use some file viewer software such as "notepad" or "text editor" to open the files in the folder. 4. If there are e-book files in the folder and sub-folder, you can try to use some file viewer software such as "notepad" or "text editor" to open these e-book files to view the contents. If none of the above methods can solve the problem, then you can try using some professional file viewer software such as "ES file browser" or "iBooks" to open the files in the e-book folder. If these files can't be opened, then the e-book file might be damaged or the file format isn't supported by the phone. In this case, you may need to back up the e-book file to another storage device and then download or purchase the e-book file again.