Doubt regarding extended warranty

I’ve ordered a laptop that's getting delivered on 9th August. There’s an offer to buy 3 years of extended warranty for ₹4000 right??. I want to know after my laptop is delivered how many days will the warranty offer be valid?

Do I need to purchase it on the same day, or is there a grace period (like 7 days, 14 days, or more)? Would appreciate response from anyone who has claimed the offer recently