How do I sync my music downloaded on my desktop to my iphone?

How do I sync my music downloaded on my desktop to my iphone without the apparent mandatory subscriptions to yet another apple product?

I no longer have iTunes only the Apple music icon. I've gone to settings and music, and there is no sync because I don't have the fee-based apps that Apple is trying to force on consumers. Is there a way to sync all of my devices so that my music purchased from Apple is on all devices?

Any help would be appreciated.