Section 194 ia practical aspects

1) It is irrelevant whether registration has been done or not, you need to deduct TDS at the time of payment or credit, whichever is earlier.

2) If registration has not been done then there must be an agreement in which it will mention payment terms and the property details.

And for being in safer side there must be an agreement otherwise later on the seller can say that we were talking about different property and not the one against which you made the payment.

Without agreement how you can pay the advance money not only that you must be aware about the property which you are going to purchase, whether it is completed one or still construction work is going on.

So, If you will go through the Form 26QB, in which there is a column where you need to mention either the agreement date or date of booking of the property, It does not ask for the date of registration.

You can refer the below link for Form 26QB format:

https://onlineservices.tin.egov-nsdl.com/etaxnew/PopServlet?rKey=-792511896