One solution that you can back up your hard drive is to sign up for a cloud storage service and guarantee that every important file is now synced to the web. This is a rather simple method yet it may cost you some dollars to use the service for the online storage space as most services only provide you with a little space for free.
Dropbox has long been among the top providers in this area, integrating with Windows and macOS while providing applications for Android and IOS so you can access your files no matter where you are. You will receive 2 gigabytes for free and paid plans will start from 10 dollars per month for from 2 Terabytes of online space.
Google Drive is another backup service, which provides Windows and macOS applications for that specific purpose. You can opt which bits of your hard drive will be backed up to the cloud, and get your files via a browser or directly from your phone. Users will receive 15 gigabytes of space for free, with paid versions starting from 100 Gigabytes for just 2 dollars a month.
There are other cloud storage services provided by Microsoft and Apple, which work well with both Windows and macOS. For instance, Microsoft offers One Drive, which is integrated into File Explore. You will receive 5 Gigabytes of space for free then the paid version starts from 2 dollars a month for 100 Gigabytes of space and more.
When it comes to Apple, iCloud is more and more important for macOS, in which there are automatic syncing options for your desktop and Documents folder have been highly improved recently. Many apps now depend on it. Your iCloud Drive has its own entry in Finder and when you may run out of the 5 Gigabytes of Apple free space, you can pay around 1 dollar a month for 50 Gigabytes of cloud space and more.
Backing up is really effective and cheaper than it used to be. If you have already had something in place, you will not need to think much about it.