When you create the backup of the selected database, you have a choice between 4 options:

1) To create and download a MySQL dump of the database - the database will be exported and saved in a file with extension .sql , which you can download and later execute on a tool like PHPMyAdmin to create it again

2) To download it as a .zip file - it will create again a backup of the database like MySQL dump, but also .zip it first before the download starts

3) To create a backup and send it your email address - the backup will be sent using the mail / SMTP server as you have set it on the Settings page and you can also enter in the text box the email address to which you wish the backup file to be sent

4) To send by email the backup as .zip - it's similar to the option above except that it will first zip the file before sending it

The check box at the bottom of the page "Save a copy in the backup history " allows you to specify if you wish also a copy of the backup to be kept in the history (so you can later download it again from the History page in the DB Backup Tool admin panel).