Apple has released iTunes 12.6.3, which reintroduces the ability to download App Store apps and ringtones from within the iTunes desktop software. However, this update isn’t targeted to the general end user.
Apple offers Volume Purchase Programs and Apple Configurator on Mac to help enterprise environments manage and mass-deploy apps on iOS devices. However, the company says that “certain business partners might still need to use iTunes to install apps,” which is why iTunes 12.6.3 is available.
If you've already installed a newer version of iTunes, you can download this version of iTunes on your Mac, PC 32-bit or PC 64-bit and run the installer. After installation is complete, you can continue to deploy apps with iTunes. You won’t be prompted to download new versions of iTunes after you install this version.