Penny stock purchases require a limit price order.
Personally, I raise my limit price a few cents above the current price so that a majority of my order would be filled. Otherwise, I will paying more in fees to my brokerage firm than for actual shares. Be careful with your stock purchases because you don't want to short this one.
Many years ago, my brokerage firm made an error in my account concerning another stock that I thought was in my advantage. When I sold the error (thinking I had made a large profit), I got a phone call a half hour later from the broker telling me that I had created a short on the stock & needed to buy the shares back immediately. 15 sweat filled minutes later & significantly poorer, I had covered my stupid decision. A mistake made but a valuable lesson learned on what not to do. By the way, I will never short a stock but I will purchase put options which is much safer & limits your loss if the trade goes wrong.