In case you want to alter the assessable value and tax rate in invoice, allow modification of tax details in F12: configure .
To override the assessable value and tax in an invoice
1. Go to Gateway of Tally > Accounting Vouchers > F8: Sales .
2. Click I : Item Invoice to record the sale in the item invoice mode.
3. Press F12: Configure .
● Set the option Use common ledger A/c for item allocation? to No .
● Set the option Allow modification of Tax Details for VAT? to Yes .
4. Select the party ledger in Party's A/c Name option.
5. Enter Party Details , as required.
6. Select the required sales ledger.
7. Select the Name of Item from the List of Stock Items .
8. Enter the Quantity and Rate .
9. Select the sales ledger in Accounting Details screen.
10. Press F12: Configure in VAT Details screen and enable the following options:
● Allow override Assessable Value?
● Allow override Tax Rate?
11. Select the Classification / Nature in VAT Details screen.
12. Enter the required Tax Rate and Assessable Value . The VAT Details screen appears as shown below:
13. Accept the VAT Details screen, and Accounting Details screen.
14. Select the CST Ledger . The sales invoice appears as shown below:
15. Press Ctrl+A to accept.