Does IOS let you download music and videos from internet apps?

I have an android device and I like downloading music and videos from internet apps. But if I switch to iOS do the iPhones let you download music and videos from internet apps too?

Nope. Apple removed most of those downloader apps a while back. Apple prefers that you either buy your music on iTunes, or subscribe to Apple Music.

You can, however, use iTunes on your PC (it's not very good) to sync music to your phone. As and Android user, you might not like doing this.