Adding app to School Managed devices
Can you explain how I can remotely add an app to a managed device?
Since this is in the iPhone community board, and since the question is lacking in detail, I will assume you are trying to deploy apps to an iPhone or iPad, that you are the admin since you mention "remotely add," and that you are in a region other than the European Union.
If your devices are "managed" by the school, then the Apps are delivered via the school's MDM. But let me take one step back from that. The school should have access to Apple School Manager (ASM). It is through ASM that the school will license or purchase applications from the App Store. Apps can be licensed/purchased in bulk. Once the apps are purchased, the Volume Purchase Program (VPP) token from ASM is imported into the MDM. The MDM will now allow setting the behavior of app delivery. Do you want the app on all devices? Some devices? To auto-install or be available via Self Service? The apps are fetched from the App Store so there is nothing for you, the admin, to download, package, or store. You simply need to assign the apps to devices.
If the devices are not enrolled into an MDM, then there will be no way to "remotely add" apps to the devices. Individual Apple IDs will be needed to add software. For institutional devices, this should be avoided in favor or ASM and VPP. (There is the Apple Configurator method but that is beyond the explanation length of this forum.)
And one final note. If devices are user-initiated enrolled, all apps pushed by the MDM will require user approval to install. If the devices are automated enrolled (DEP), then the apps will automatically install with no user interaction.
Hope this is helpful