Creating backup copies of your quiz is enabled by default. You can turn on/off backups creation option in the Application Menu -> Options.
To back up your quiz, switch on the 'Automatically create quiz backups' option.
If the option is enabled, a backup file of the previous version is created each time when you save a quiz. Each new backup copy replaces the previous backup copy. QuizMaker saves the backup file in the same folder as the original quiz. The name of the backup file adds the word 'backup' to the file name, for example: Sample_Quiz.quiz and Sample_Quiz (backup).quiz