Your question isn't clear. If you have sold a naked put, you would buy it to close to end the contract not Sell the option at that price, if ITM.
There are 3 possibilities at expiration.
1) The put is out-of-the-money and it expires worthless
2) It is in-the-money and you buy it to close from either another trader or the market maker
3) It is ITM and you do nothing and it is automatically assigned by the OCC
Why automatic? If an option is one cent or more ITM at expiration, the Option Clearing Corp (OCC) will automatically exercise all options whether they are long or short. This is called Exercise by Exception. For equity options, you will end up with a position in the underlying (index options are cash settled).
If you are long the option, you can designate to the OCC via your broker that your options are not auto exercised at expiration. This would make sense if they are ITM by pennies and your commission to close the position exceeds the ITM amount.
If short the ITM option, you need to take action if you don't want assignment and a position in the underlying.