Hi Abdul,
Please check below Query.
SELECT DISTINCT T1.[DocNum] AS 'Order No:', T1.[DocDate] AS 'Posting Date', T1.[NumAtCard] AS 'Reference No.',
T1.[CardCode] AS 'Customer Code', T1.[CardName] AS 'Customer Name', T1.[DocTotal] AS 'Invoice Amount',
T1.[DiscPrcnt] AS 'Discount (%)', T1.[DiscSum] AS 'Discount Amount', T1.[VatSum] AS 'Tax Amount',
T1.[DocTotal] AS 'Net Amount (After Discount)'
FROM [dbo].[RDR1] T0
INNER JOIN [dbo].[ORDR] T1 ON T1.[DocEntry] = T0.[DocEntry]
WHERE T1.[DocDate] >= (CONVERT(DATETIME, '[%0]', 112) ) AND T1.[DocDate] <= (CONVERT(DATETIME, '[%1]', 112) )
Hope this helps 
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Regards::::
Atul Chakraborty