Is eInvoice is required for exempted goods to registered dealers - B2B

Our client is manufacturing the dairy products and have turnover of more than Rs100 Cr. We are raising e-Invoice for both taxable and exempted goods, since our invoice is consist of both taxable and exempted goods. Should we need to raise e-Invoice for taxable goods only or Are we need to raise eInvoice for both.

How to pass credit note for price difference discount for exempted goods in GSTR1 Return.