The coding will be made automatically based on the part's product group, if an account has been registered in the Product Groups procedure for the product group to which the part belongs.
By clicking the C button a coding window opens where you, if needed, can change the purchase account. Cost center, cost unit and project can be entered/deleted, depending on how the account has been configured in the chart of accounts regarding "Yes"/"No"/"Mandatory"/"Warehouse"/"Warehouse - Mandatory".