Thanks you all for Reply
But when I am adding the document without attachment file than Add A/P invoice with out validation.
For this Problem i have create two UDF link type and attach TN in UDF
like this-->>
IF (@object_type = '18' )and (@transaction_type IN ('A','U'))
BEGIN
If Exists (Select DocEntry from OPCH
where U_P = 'XYZ' and DocEntry = @list_of_cols_val_tab_del
AND U_BILL is null
)
Begin
set @error =6
set @error_message = 'Please attach the scanned copy'
End
END