You can back them up on either an External Hard Disk Drive or a cloud drive. Cloud is the safest way to store your data, as they keep multiple copies of your data. And if you’re going to try to restore it on your own personal computer, you won’t be able to get your data back when it crashes.
If you have an external USB hard drive, using the built-in backup functionality of your computer, you can just back up to that drive. Use File History on Windows 10, and 8. Use Windows Backup, on Windows 7. Using Time Machine on Macs. Occasionally connect the drive to your computer and use the backup tool, or leave it in when your home is plugged in and it will automatically back up