You can create any number of issue types. Go through the following steps to create a new issue type:

1. Browse to the Issue Types page
2. Click on the Add Issue Type button
3. Enter the name and description for the new issue type
4. Select whether the new issue type will be a standard issue type or a subtask issue type
5. Click on Add to create the new issue type

Once the new issue type has been created, it will be assigned a default icon. If you want to change the icon, you will need to click on the Edit link for the issue type and then select a new image as its icon.