appsettings.json

{
  "MyConfigValues": {
    "Hello": "My Values"
  }
}

My Data Holding Class

public class MyConfigModel
{
    public string Hello { get; set; }
}

Startup.cs

public class Startup
{
		...

    public void ConfigureServices(IServiceCollection services)
    {
        ...
        services.Configure<MyConfigModel>(options => Configuration.GetSection("MyConfigValues").Bind(options));
				// Alternative:
			  services.AddOptions<MyConfigModel>()
		        .Bind(Configuration.GetSection("MyConfigValues"));
				...
    }

		...
}

Controller

[Route("api/[controller]")]
[ApiController]
public class TestController : ControllerBase
{
    private readonly IOptions<MyConfigModel> config;

    public TestController(IOptions<MyConfigModel> config) => this.config = config;

    [HttpGet]
    public ActionResult<MyConfigModel> Get() =>
        Ok(this.config.Value);
}