What is the difference between the two shuffle icons? One is where the two arrows touch and the other where the two arrows are over each other? I know it's probably a simple question.
If your talking about the stock music player for iOS devices on iOS 10, the 'two arrows that are over each other' IS the shuffle function selector: tap it once to highlight it (turns on the shuffling of the currently selected tracks), tap it again to deselect it and turn off shuffling. As for the icon (button) where 'the two arrows touch' that is actually the repeat function: tap it once to repeat the music (tracks) that you started playing... There IS a caveat to this though, if you add more tracks via either the 'Play Next' or 'Play Later' options in the options menu denoted by three dots (...) those added tracks will play only once for each track that was selected that way, when they are gotten to in the order of playback that they were selected. Then, once those tracks have finished playing back, the original cue of tracks will continue to play on repeat. Tap 'the two arrows that touch' a second time to select the currently playing song to be on continuous repeat, which will be denoted by the number '1' inside of the arrows. Unless of course, if it was a song added by either the 'Play Next' or 'Play Later' options in which case it will play only once. As well, these 'Play Next' or Play Later' tracks won't even have the shuffle or repeat icons show in the music player when they are the currently playing song. And then, to turn off the repeat function of your music's playback, tap the repeat icon a third time to deselect the repeating of your music. This information also applies to music playback in the current version of iTunes 12.5.x