Your Vivo 8 has a MicroSD memory card reader. If your personal computer can also read that card type (Most laptops are so-equipped), you should be able to save a music file
The BLU Vivo 8 is an Android phone and there are plenty of free ringtone apps such as MP3 Cutter, RingDroid (open source) and more.
More on free ringtones
Here are some of the 100% free ringtones (BLU Vivo 8-compatible) offered here at MartinsRingtones.com:
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