Volumes Support

Volumes are network-based block devices that provide additional data storage for Droplets. You can move them between Droplets and resize them at any time. Learn more about volumes.

No; however, you can add another layer onto your Droplet with an attached Volume.
Adding a volume to your Droplet doesn’t increase its main disk size. You need to resize the Droplet to increase its main disk size.
Filesystem tools often don’t report the capacity reserved for metadata and the root user, and some report size in different units.
You cannot currently download DigitalOcean backups or snapshots, but you can use third-party tools to save your data locally.