If you save data to 'The Cloud' you can access it from anywhere. If your computer dies, you will not be able to access a USB drive, or data on a CD.
There are many 'cloud' services, many come with 'free' storage and you can purchase extra as needed. Google Drive, One Drive (comes with MS Office), iCloud (comes with Apple account) are three that I use.
Another option that I used prior to 'cloud' was to email files to my gmail account. I get 15 GB of storage.
It is important to think about how you will access the data you have stored. Is it a long term back up? Do you need to access it from other locations? Do you need to move the files between devices (computer to LA, phone to computer etc).
Then there is the issue of local and off site storage. CDs, USB, external hard drive etc, are all examples of local storage. You have a back up, but it is not safe from a disaster. There were photos here recently of a LAQ who had lost everything in a fire. A devastating experience, for her and her family. Cloud storage is off site, but not without risks. Cloud sites could be hacked, they can go 'down', they could have a catastrophic incident.
Me, I use One Drive and have a mirrored copy of my One Drive on my computer. I use Google Drive to share files between various groups I belong too (not copy written material.) I save all my photos to iCloud.