No. Attendance codes are defined by the DfE. Please look at the information in your system Register>Notes and click on "Open Register Codes Summary" You can also look at government guidelines here https://www.gov.uk/government/publications/school-attendance
You can however add your own Staff Attendance Codes by going to Admin > Personnel > Staff Absence Codes, in here you can match your own description of absence to the DfE codes.