If it is a market order, it will execute at the price when the market is open, even if its much higher.
The prices are live and will fluctuate. It's important to ensure you have enough funds to cover the price of a stock, as it can go up when purchasing and if the funds are not available then the order will not execute. As long as you make sure to have enough funds, then the orders will be successful upon the market opening.
If it is a limit or stop order, it would only execute at the price that you input.
As for How long it takes, if you're asking about the time funds take to settle , then trades take 2-3 working days to settle. Our brokers apply the T+2 rule (trade date plus two days).