Exporting your game
Quality Settings
In Edit > Project Settings > Quality, you can adjust which quality settings are available on which platform and what each of those quality settings changes as well. For more information on what these quality settings can do, please visit https://docs.unity3d.com/Manual/class-QualitySettings.html.
Unity Services
There's a lot of things Unity can do for you, with Analytics and Multiplayer, and etc, but we're only going to talk about Collaboration and Cloud Build for now.
Cloud Build
Collaborate
Build & Run
If you've been following along you should have your quality settings all the way you wanted them.
Now you should check File > Build Settings and make sure everything looks right in there, such as what scenes you want included, your target platform, whether or not this is a development build vs being official and stable. Then you can pick build, or build and run if you'd like to test it and your system is one of the targeted platforms. You could also set up Unity Cloud Build so your builds get pushed to Unity's cloud database for your account.