For questions about programmatic usage of the styling features in Google Maps Platform, which allow maps to be styled and customized.
You can apply customized styling through an embedded JSON style declarations or via Cloud-based map styling (Select your platform when reaching these links).
For JSON Maps Styling, you can use the Maps Platform Styling Wizard to construct and export the JSON declarations.
If you want to easily update the same style across multiple apps, look into cloud customization, available in the Google Cloud Console. You will need to create and add a map ID to use cloud customization.
Google recommends not combining cloud customization and hardcoded styling in the same app, to avoid potential future conflicts.