What it is
A sale deed is the legal instrument recording a completed sale of immovable property — it names the seller, the buyer, the property description matching the survey number and subdivision, the sale consideration, and the terms of transfer. It becomes valid only once registered with the jurisdictional sub-registrar office, with stamp duty and registration fees paid. An unregistered sale agreement is not the same as a sale deed; only a registered deed conveys title under the Registration Act.
Why it matters when you buy
The sale deed is the direct evidence of your chain of title, so its details must match every other record: survey number and subdivision on the patta, the extent on the FMB sketch, and the seller's name on prior deeds in the encumbrance certificate. Any mismatch is a red flag to resolve before registration. After registering the deed, remember the revenue record does not update automatically — you still need to apply for patta transfer to have your name recorded as the holder.
Where you find it
You register the sale deed at the sub-registrar office covering the property's location, and can retrieve certified copies later through tnreginet.gov.in or in person. The registered deed's document number and date are what an encumbrance certificate search cites, so keep them noted along with the property's survey number — you will need them again whenever you order an EC or apply for patta transfer.