ServiceNow (NOW 0.09%) is one of the biggest software companies on the stock market, and it's also been a top performer for much of its history.The company's core Now platform is used for a wide range of IT management tasks, as it acts as a hub for managing, processing, and automating workflows. Among the applications that businesses use it for include inventory and supply chain operations, customer relationship management, and for cybersecurity.That flexibility has helped make the stock a winner, and it se ...