Tds certificates

Form 27A is like a covering sheet submitted to the NSDL by the Deductor at the time of filing TDS return. It has details like total amounts paid and total TDS deposited.

Whereas forms 16 and 16A are TDS Certificates issued by the Deductor to the Deductee which contains details of sum deducted from their income. The deductees use these Certificates to feed in the amount in their TDS A/c while filing Income Tax Return to lower their Income Tax liability (This amount is like advance tax paid by the deductee).

Hope I'm clear