Management of apps, books, and tones has been removed from iTunes 12.7. See Changes in the new iTunes - Apple Support for details.
See the Manually add items from your computer section of Manually manage content on your iPhone, iPad, or iPod touch using iTunes - Apple Support for the control that remains. This can be used to copy apps, iBooks, ePubs, PDFs, and tones from your computer to your device. The File Sharing feature for copying data between apps and the computer is still there. You can also use iCloud Drive, Dropbox, or other cloud services to move content to the device.
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