A public company means that the stocks can be freely traded on a stock market. This is opposed to a private company where the stocks are traded in private transactions. Because investors want the value of their assets (their stocks) to go up (so they can resell them for a higher value), the company has to keep increasing it’s revenue
FYI the Simple Mobile Tools suite sold out to a scam company: https://www.youtube.com/watch?v=OGr4H7QLVRs
One of the contributors was going to start a fork, but it’s something to keep in mind.