Parsec is a game streaming software that prioritizes latency, frame rates, and video quality for high performance 3D graphics. There are several ways to get connected to a host gaming PC. You either need to set up a host PC (Parsec host only works on Windows at this time), be invited by your friend to connect, jump into a Party to find a random person to play games with, have a link to connect to another gaming PC, or build a cloud gaming PC.
If you'd like to change the resolution or video quality, you can change your hosting settings on the computer you're connecting to, in Hosting settings tab.
If you would like to change how your Parsec stream window is displayed, and if immersive mode is enabled, you can view the Client settings on the client computer.