Just under a month ago, in the early part of September – Apple released iTunes 12.7 for macOS and Windows and this release removed the App Store section, as well as the ability to manage and download ringtones.
Now, earlier today Apple has re-released the old version of iTunes, 12.6.3 for macOS and Windows with the addition of the App Store once again as well as the option to download ringtones, direct from the iTunes Store. This is a very ‘un-Apple’ thing to do, this kind of thing rarely happens, but Apple has chosen to re-release an older version of iTunes, simply because:
“certain business partners might still need to use iTunes to install apps.”
Source: Apple Support Document