can i download mp3 files in my ipad air?

Hello, I tried to play mp3 files from a website like I always did. Since update to IOS 8.1 it doesn't work anymore. Then I searched a way to download them into the Ipad air for offline use. Didn't find any.

I could play the files on the Ipad only if I sent them as email attachments to my own email address from a PC, but could play them only within the email. Tried to download or copy them into the Ipad.

Please help me find a way to do this, it is very important to me, because these files are training files for choir voices, I sing in this choir and I need the exercise. Greetings from Grueni