can I transfer music from my ipad to my iphone without itunes on my pc

Your iPad should never serve as your music repository - the primary place where your music is housed. (By the way, neither should your iPhone.)

If you happen to subscribe to Apple Music, your music would be available on all your Apple devices. The same would be true if you subscribe to iTunes Match once you initially populate your iCloud Music Library with all your music.

If you subscribe to neither of the above, a computer is required to get your music to your iPhone.