Question about taking delivery of shares for sold put option

I hv a question about selling a put option and taking delivery of shares. For example, I want to buy M&M stock at ₹2900 (current market price: ₹3085). So I sell a PUT option with a ₹2900 strike price and collect certain premium. If share price falls to ₹2900 or lower by expiry date, will I automatically receive the shares at ₹2900? Also if stock keeps dropping below ₹2900 do I need to worry about extra costs or adjustments due to changes in the premium? If i am correct, in any case i should be allotted shared at ₹2900 regardless of share price dropping to any level?