Where is the "download all" button for itunes music

not on my phone there isn't, but my sister and i both bought an iphone 6 yesterday and her iphone has the option, mine doesn't, that's why i assumed there was a setting somewhere that allowed it to show. Her phone you go to itunes ap> more> purchased> music> then you get to the bit where it has all of the music, at the top of her phone she has "recently purchased" and "all music" when you go into "all music" it has a download all button!!! with my phone, it has not got the "all music" it only has the "recently purchased" they are both brand new iphone 6 with no data yet on them. I'm confused as to why hers has the function and mine doesn't. There must be a setting somewhere but i've looked and looked and there's nothing. I literally have THOUSANDS of songs, this would take me forever to go into every album. Irony has it that my sisters only has about 300 songs and go figure hers is the one that can download all 😟