Currently to support you in recording non attendance in accordance to the DfE Guidance there are only Subcodes for I and X codes.
The examples and screenshots in this guide are for illustration purposes only and may differ from your schools view.
See also; How to Distribute Attendance Codes and Subcodes from within Vision
For DfE information on attendance see here.
To adding further Subcodes for your own recording of attendance go to Config>Attendance>Attendance Codes.
This will take you to the Attendance Codes panel.
Click on the required Attendance Code and the Manage Subcodes green button will appear on the top left.
Click Add New Record
When you click Add New Record a blank box appears.
In the first box you need to add a three digit code, this must start with the original attendance code that you are adding a Subcode to. The second box is where your description is added.
Please use the Tick at the end to save the new code.