If the sales invoice shows an incorrect tax amount and you need to modify tax rates and categories for a saved invoice, you can follow these steps.
Step 1. Ensure that the tax rates and categories are set up correctly.
Step 2. Check the transaction details, such as item prices, quantities, and tax codes, to ensure they are entered accurately.
Step 3. Verify the sale type or purchase type you have selected in the voucher.
Step 4. To change the tax category, go to Administration, select Masters, then click on Items, and finally click on Modify.
Step 5. Select the item and change the tax category. If you want to create a new tax category, press F3 on the tax category and create it.
Step 6. Go to Transactions, click on Sales Invoice, then click on Modify and select the voucher.
Step 7. Change the sale type or make any other necessary modifications.