Input tax credit is a mechanism under GST that allows registered taxpayers to claim credit for taxes paid on inputs and capital goods. This helps remove cascading of taxes and ensures only value added at each stage is taxed. Taxpayers can utilize input tax credit to offset output tax liability, and only pay the net amount. Some key conditions for claiming ITC include possessing valid tax invoices, actual receipt of goods/services, and taxes being paid by the supplier. Unutilized credit can be carried forward or in some cases, claimed as a refund. Strict matching and reconciliation rules apply to verify ITC claims.