There are a number of custom fields on Customer, Stock, and Nominal Records.

Navigate to System > Options > Custom Fields; from here you can select which custom fields you wish to use. The fields that are selected here are then set as being available to add to the relevant record.

On each tab you have access to a number of Text fields, Numeric fields, Date fields, and Boolean (Yes/No) fields.

Compulsory - (where available) On entering a sales order, if any of the custom fields has been marked as compulsory then the Custom Field window will pop-up automatically. Fields become compulsory when entering orders from SOP or when editing from the batch.