While Enter Purchase voucher TDS window not showing in voucher.
If you want to apply tds in purchase but still window not showing while voucher saving ,even feature already enable from tds or tcs tab you may check following things:
1: Check in the party master that you enable the the tds option and speciFinancial Year the payee category in party master.
2: Check that net amount of invoice should cross the threshold limit if selected applicable after limit in tds on payment field in tds details window.