Using a string (such as user input) to call information from an array or variable

I suggest implementing a Person class:

  public class Person {
    private static List<Person> s_Persons = new List<Person>();

    public String FirstName {get; private set;}
    public String LastName {get; private set;}
    public String Phone {get; private set;}
    public int EmployeeNumber {get; private set;}

    public Person(String firstName, String lastName, String phone, int employeeNumber) {
      FirstName = firstName;
      LastName = lastName;
      Phone = phone; 
      EmployeeNumber = employeeNumber;

      s_Persons.Add(this);
    }

    public override String ToString() {
      return String.Join(" ", FirstName, LastName, Phone, EmployeeNumber);
    }

    public static IReadOnlyList<Person> Persons {
      get {
        return s_Persons; 
      }
    }
  }

And then you can use Linq for various queries:

  var Bob = new Person("Bob", "Belcher", "800-123-12345", 13483);
  var James = new Person("James", "Bond", "555-123-6758", 13484);
  var Clark = new Person("Clark", "Kent", "111-222-3333", 13485);

  // Let's print out all the persons with "Bob" first name
  var allBobs = Person.Persons
    .Where(person => person.FirstName = "Bob")
    .OrderBy(person => person.LastName);

  Console.Write(String.Join(Environment.NewLine, allBobs));

  // Let's find Employee number by his/her first name and ensure that there's
  // only one such a person:

 int number = Person.Persons
   .Where(person => person.FirstName = "Bob")
   .Single()
   .Select(person => person.EmployeeNumber);

The variable variable $$input construct from PHP doesn't work in C#. What you could try in this case is keep your arrays in a dictionary and use the input to look up the entry.

Dictionary<string, string[]> values = new Dictionary<string, string[]>()
{
    { "Bob", new string[] { "Bob", "Belcher", "800-123-12345", "13483" } },
    { "James", new string[] { "James", "Bond", "555-123-6758", "13484" } },
};
string input = Console.ReadLine();
Console.WriteLine(values[input][3]);

Put your arrays in a dictionary:

IDictionary<string,string[]> byName = new Dictionary<string,string[]> {
    {"Bob", Bob}
,   {"James", James}
,   {"Clark", Clark}
};

Now you can do this:

if (byName.ContainsKey(input)) {
    Console.WriteLine(byName[input][3]);
} else {
    Console.WriteLine("Wrong name: {0}", input);
}

Depending on the value of input you'll get the correct array.

Typically, though, you would not make individually named variables to represent individual objects in a collection, and you wouldn't store a person's info in a flat array of strings, using a custom Person class instead.

    string[] Bob = { "Bob", "Belcher", "800-123-12345", "13483" };
    string[] James = { "James", "Bond", "555-123-6758", "13484" };
    string[] Clark = { "Clark", "Kent", "111-222-3333", "13485" };

    // create a collection of arrays
    var list = new List<string[]> { Bob, James, Clark };

    string input = Console.ReadLine();
    // User types in Bob

    // Search in the list. Compare user input to [0] element of each string array in the list.
    var userChoice = list.FirstOrDefault(x => x[0] == input);

    if (userChoice != null)
    {
        Console.WriteLine(userChoice[3]);
    }

Make a list of your string arrays and loop over. like:

List<string[]> list = new List<string[]>();
list.add(Bob);
foreach(string[] s in list)
{
  if(s[0] == userinput)
     Console.WriteLine(Bob[0]);
}

The Code isnt tested just by the way.