There are stock split date for every share after announcement.
On the day of split , you can see the prices going half and also generally there is an upside move upto 5–8% as investors who are willing to hold more shares get it for a cheaper price. It is completely sentiment driven.
The stock split credits your demat account on the very same day however it is advised not to sell the shares on same day of split as at times the procedure may not be completely clear or the broker is not active and he penalizes you for short delivery/selling.
Answering your question, The account is credited by shares on the day of split, you can sell if you want but it is advised not to sell until next day.
Every broker has its holding technology and they can tell you how many shares you hold to confirm them before selling.
If zerodha is broker then you can see the holding in their software itself.
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