Re: How can I add music to my Samsung s6 active? What is the best app to use?
I usually just copy files from my PC to my phone if I have music I want to put on the phone (assuming it's not single-copy-use licensed). For example, I have a copy of the full performance of "Thus Spake Zarathustra" (the theme of 2001: A Space Odyssey) on my phone because I love the piece. Just copied a Creative Commons licensed recording to the phone - simple. (I have a folder on my SD card named mp3 for music.)
If you have a particular folder/file organization on your PC (like artist/album/tracks here), copy the whole top folder and you'll keep the organization. (I prefer doing it manually, rather than the Music Manager link Laura gave, because then I'm certain what's going where, and I can skip or add anything I like. Then again, it took 3 years to drag me from DOS to Windows.)