TDS, or Tax Deducted at Source, is a system where the person or entity paying you money — such as your employer, a bank paying interest, or a client paying fees — deducts a portion of tax right at the time of payment and deposits it directly with the government on your behalf, rather than you having to pay that tax yourself later.
You still receive the remaining amount after TDS, and the deducted tax is credited against your final tax liability when you file your income tax return — if too much TDS was deducted relative to what you actually owe, you get the excess back as a refund. TDS applies to many types of income, including salary, bank FD interest above a threshold, rent, and professional fees, and you can verify how much TDS has been deducted using Form 26AS or the AIS.