How to pass user details remotely?

I need to a create api call, which can allow user's to login from a remote platform and access  Data api controller.  Could some one please provide some assistant in how can I pass the user's details.  

I need to pass user's login details, so the users can login to view data api controller.

This is what my login class looks like:

using System;
using System.Collections.Generic;

public partial class api_login
{
public string ID { get; set; }
public string username { get; set; }
public string password { get; set; }
public string description { get; set; }
public string role { get; set; }
}

Any help would be very much appreciated. 

Thanks