How to download free music to my IPhone 6s?

I just got my IPhone yesterday and this is my first apple product so I don't know how to get free music via apps and whatnot. I have music downloaded on my Google Drive but I don't know how to get that onto my phone. Can someone help me move that music to my phone/find me an app that will allow free music downloads? Thank you in advance!

Added (1). I also can't download ITunes on my laptop because I have a chromebook

Sign up for the free 3 month trial for Apple Music. It allows you to download music for offline viewing. Other than that you'll have to pay, there maybe other trials such as Spotify Premium

Please keep in mind that you can download/share only copyright-free material for free, unless the copyright owners allow free downloading/sharing of their material. All sites and resources that provide COPYRIGHTED material to be downloaded/shared for free, but WITHOUT permission from the copyright owners are equally ILLEGAL! So, unless you are about to download copyright-free material, please start using legal buy-a-download resources ONLY. Having no money/credit card is NEVER an excuse to STEAL anything anyway, so there's a very good reason why all the ILLEGAL sites/resources are being shut down and their users being sued for illegal downloading. It is also the reason why there's NO direct download button available on YouTube.

NOT all in music business are super rich, besides, all the studio engineers, backing vocalists, instrumentalists etc. DO deserve to get paid for the sheer hard work they do in order to make the music for us. I very much doubt YOU would work for 30+ years without getting paid either.