How to give privilege to login Administrator and Invited in C#

<big>//Login Form</big>
namespace GESTAO_CLINICA
{
    public partial class frmLogin : Form
    {
        public frmLogin()
        {
            InitializeComponent();
            txtsenha.PasswordChar = '*';
        }

        <big>//Button Save</big>
        private void button2_Click(object sender, EventArgs e)
        {
           
            try
           {
                string sql="Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=db_Maried;Data Source=TOBE-ANGOLA-PC";
                SqlConnection conn=new SqlConnection (sql);

                SqlCommand cmd = new SqlCommand("select UserName,Senha,TipoConta from tb_login where UserName='" + this.txtUsuario.Text + "'and Senha ='" + this.txtsenha.Text + "' ;", conn);
                SqlDataReader leitura;
                conn.Open();
                leitura = cmd.ExecuteReader();
                int count = 0;
                while (leitura.Read())
                {
                    count = count + 1;
                }
                if (count == 1)
                {

                    this.Hide();
                    Form1 c = new Form1(txtUsuario.Text); //Principal Form (Desktop)
                    c.ShowDialog();


                }
                else if (count > 1)
                {
                    //MessageBox.Show("Usuario ou senha Duplicada....Acesso Negado");
                    label3.Visible = true;

                    label3.Text = "Usuario ou senha Duplicada....Acesso Negado";
                }
                else
                {
                    //MessageBox.Show ("Usuario ou senha Errada....Por Favor Tente de Novo");
                    label3.Visible = true;
                    label3.Text = "Usuario ou senha Errada....Por Favor Tente de Novo";
                }
                conn.Close();
           }
            catch (Exception ex)
            {
                MessageBox.Show("Erro", ex.Message);
            }

        }