Our system has a very specific Case Number system. This case number can only be customized slightly. Many users have their own Case Number system they would like to incorporate. To achieve that I'm going to show you where to add an information field so you can add your own Company, specific case number. 

1. Go to Case Type inside Settings under Case Customization. 

2. For this to be system wide this process needs to be added to every Case Type. Click on the Manage Custom Form Icon (far left). 

3. In this section simply take one of the fields on the right that would work for your Case Number and drag it over to the left, or if known of the fields look like they apply to you, the user can scroll down to the bottom and click "Manage Custom Field" to create their own.