Purchases from unregistered dealers are exempt. You need to identify the party as an unregistered dealer.
Update the party ledger to identify unregistered dealers
1. Go to Gateway of Tally - Accounts Info. - Ledgers - Alter - select the ledger.
2. Set the Registration type as Unregistered.
3. Press Ctrl+A to save.
Record purchases from an unregistered dealer
1. Go to Gateway of Tally - Accounting Vouchers - F9: Purchase.
2. In Party's A/c Name, select the ledger of the unregistered dealer.
3. Select the purchase ledger created with Domestic Exempt Purchases as the Nature of transaction.
4. Select the stock item, and enter the quantity and rate.
If you are using a common purchase ledger, then based on the party ledger, the nature of transaction is inferred as Domestic Taxable Purchases - Unregistered. To change the nature:
● Click F12: Configure in the purchase invoice and set the option Allow modification of tax details for VAT? to Yes.
● Select the Nature as Domestic Exempt Purchases in the VAT Details screen (displayed on pressing Enter from the Amount column of the invoice).
● While saving the invoice, press O to override the invoice with the new nature of transaction.
5. Press Ctrl+A to accept.