Unity doesn't offer a savegame system out-of-the-box. You won't get around writing and reading files yourself using the usual file access tools the .NET standard library offers (check stackoverflow.com about how to read and write files in C#. That topic got asked and answered to death by now).
But Unity comes with one class which can make your life a lot easier:
JsonUtility. This class allows you to convert objects to JSON strings and back. You can only use it on classes which have the
Note that it will only serialize/deserialize
public variables and attributes.