A backup is a copy of important data that is stored in an alternate location, so it can be recovered if it is deleted or corrupted. Depending on how often the data changes, how valuable it is, and how long it takes to back up, it will determine how often the backup will be performed.
Why is it important
A computer could stop working at any time and the data on a hard drive could get corrupted or lost if the hard drive fails. When the hardware or computer stops working, the data on the computer could be lost. All important files should be backed up to avoid data loss and ensure that you can recover those files if necessary.