Placing Routes in Multiple Files/Folders Using Minimal API in .Net 6

you can create an external module that is called from program.cs passing the IApplicationBuilder.

AddMyApplicationRoutes(app);

or as suggested make it an extension:

app.AddMyApplicationRoutes();

This is a working example of what I interpreted from the above suggestions.
In a file called SomethingRegistration.cs:

namespace Something.Apis
{
    public static class SomethingRegistrationExtension
    {
        public static IApplicationBuilder UseSomethingRegistration( this IApplicationBuilder builder )
        {
            return builder.UseEndpoints(endpoints =>
            {
                endpoints.MapPost("/authenticate", async context => await context.Response.WriteAsync("Reject Something") );

                endpoints.MapGet("/confuse/{id}", async context => await context.Response.WriteAsync("Good-Bye World!!!!") );
            });
        }
    }
}

I called it from Program.cs as follows:

...
app.UseRouting();

app.UseSomethingRegistration(); // <-- My routes in another file/folder

app.MapGet( "/", () => "Hello World!" );

app.Run();

Thanks everyone!