Why is my ipad air browser keep shutting down?

Here are ssome Apple Support documents so you can know and understand what files are backed up and what is NOT backed up. Be sure to have at least two different backups from two different sources for a backup methodology ...

Choosing an iOS Backup Method (Should I Use iTunes or iCloud to back up ...)

https://support.apple.com/kb/HT5262

Back up and Restore your iOS Device with iCloud or iTunes

http://support.apple.com/kb/ht1766

iTunes: About iOS Backups

http://support.apple.com/kb/ht4946

Create and Delete iPhone, iPad and iPod Touch Backups in iTunes

http://support.apple.com/kb/ht4946

iOS: Troubleshooting Encrypted Backups

http://support.apple.com/kb/TS5162

moniquefromgatineau wrote:

Where is my music stored. Doesn't show up on backup

Your iTunes music that you've purchased is "in the cloud" always and is always available for redownload. One exception to that would be if it is no longer being sold on iTunes. In any case, you should backup your iTunes music library, even if it is still in the iTunes Store.