How to take a backup of my iPhone 5C that's on my iPad and transfer it to my computer?

I don't totally know how, but there is a backup of my iPhone from a year ago on my iPad, and I don't know how to transfer that backup to my computer, or at least access the backup file from my computer. Right now I can see it in the ipad storage settings but i can't see it from the icloud website or when i open the ipad hard drive from my computer. i'm very lost here please help, thanks