this.textBox1.Anchor = System.Windows.Forms.AnchorStyles.None;
this.textBox1.Location = new System.Drawing.Point(85, 101);
this.textBox1.Name = "textBox1";
this.textBox1.PlaceholderText = "Login";
this.textBox1.Size = new System.Drawing.Size(213, 23);
this.textBox1.TabIndex = 0;
this.textBox1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;

txtName.BorderStyle = BorderStyle.None;
Label lblBottomBorder = new Label();
lblBottomBorder.ForeColor = Color.Blue;
lblBottomBorder.Width = txtName.Width + 8;
lblBottomBorder.Text = new String('_', 250);
lblBottomBorder.Location = new Point(txtName.Location.X - 3, txtName.Location.Y + 3);
Controls.Add(lblBottomBorder);

public partial class FrmLogin : Form
{
    public FrmLogin()
    {
        InitializeComponent();
        Text = "Login";
        StartPosition = FormStartPosition.CenterScreen;
        MaximizeBox = false;
        MinimizeBox = false;
        FormBorderStyle = FormBorderStyle.FixedDialog;
        Font = new Font("Segoe UI", 10);
        BackColor = Color.White;
        AcceptButton = btnOK;
        Activated += (sender, e) => txtEmail.PlaceholderText = "Email, phone or Skype";
        lblEnter.Font = new Font("Segoe UI", 14, FontStyle.Bold);
        txtEmail.BorderStyle = BorderStyle.None;
        txtEmail.ForeColor = Color.DimGray;
        btnOK.BackColor = Color.DarkBlue;
        btnOK.ForeColor = Color.White;
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        Point txtEmailLocation = PointToClient(PointToScreen(txtEmail.Location));
        var lineStart = new Point(txtEmailLocation.X, txtEmailLocation.Y + txtEmail.Height + 7);
        var lineEnd = new Point(txtEmailLocation.X + txtEmail.Width, txtEmailLocation.Y + txtEmail.Height + 7);
        Pen pen = new Pen(Color.Blue) { Width = 2 };
        e.Graphics.DrawLine(pen, lineStart, lineEnd);
    }
}

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using System.Windows.Forms.Design;
[Designer(typeof(TextBoxInputDesigner))]
public partial class TextBoxInput : UserControl {
    private string m_CueBanner = string.Empty;
    private bool m_CueBannerShowOnFocus = true;
    private Color m_LineColor = Color.CadetBlue;
    private int m_LineDistance = 4;
    private int m_LineHeight = 1;
    public TextBoxInput() {
        InitializeComponent();
        ResizeRedraw = true;
        Padding = new Padding(3, 10, 3, 1);
        EditControl.TextChanged += (_, __) => OnTextChangedInternal(EditControl.Text, false);
        EditControl.HandleCreated += (_, __) => SetCueBanner(EditControl.Handle, m_CueBanner, m_CueBannerShowOnFocus);
        CueBanner = "<Enter CueBanner>";
    }
    public string CueBanner { 
        get => m_CueBanner;
        set {
            m_CueBanner = value;
            SetCueBanner(EditControl.Handle, m_CueBanner, m_CueBannerShowOnFocus);
        } 
    }
    [DefaultValue(true)]
    public bool CueBannerShowOnFocus { 
        get => m_CueBannerShowOnFocus; 
        set {
            m_CueBannerShowOnFocus = value;
            SetCueBanner(EditControl.Handle, m_CueBanner, m_CueBannerShowOnFocus);
        }
    }
    public Color LineColor {
        get => m_LineColor;
        set {
            m_LineColor = value;
            Invalidate();
        }
    }
    [DefaultValue(1), Description("Sets the height of the Line. Allowed values (1, 8)")]
    public int LineHeight {
        get => m_LineHeight;
        set {
            m_LineHeight = Math.Max(1, Math.Min(value, 8));
            Invalidate();
            OnResize(EventArgs.Empty);
        }
    }
    [DefaultValue(false)]
    public bool IsPassword { 
        get => EditControl.UseSystemPasswordChar;
        set => EditControl.UseSystemPasswordChar = value;
    }
    [Bindable(true), Browsable(true), EditorBrowsable(EditorBrowsableState.Always)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
    public override string Text {
        get => base.Text; 
        set {
            OnTextChangedInternal(value, true);
        } 
    }
    protected override void OnBackColorChanged(EventArgs e) {
        base.OnBackColorChanged(e);
        EditControl.BackColor = base.BackColor;
    }
    protected override void OnForeColorChanged(EventArgs e) {
        base.OnForeColorChanged(e);
        EditControl.ForeColor = base.ForeColor;
    }
    protected override void OnLayout(LayoutEventArgs e) {
        base.OnLayout(e);
        ClientSize = new Size(ClientSize.Width, EditControl.Bounds.Bottom + m_LineDistance + m_LineHeight + 1);
    }
    protected override void OnPaintBackground (PaintEventArgs e) {
        base.OnPaintBackground(e);
        int yPos = EditControl.Bounds.Bottom + m_LineDistance + (m_LineHeight / 2);
        using (var pen = new Pen(m_LineColor, m_LineHeight)) {
            e.Graphics.DrawLine(pen, 0, yPos, ClientSize.Width, yPos);
        }
    }
    protected override void OnRightToLeftChanged(EventArgs e) {
        base.OnRightToLeftChanged(e);
        EditControl.RightToLeft = RightToLeft;
    }
    internal virtual void OnTextChangedInternal(string text, bool internalCall) {
        base.Text = text;
        if (internalCall) EditControl.Text = text;
        OnTextChanged(EventArgs.Empty);
        SetCueBanner(EditControl.Handle, m_CueBanner, m_CueBannerShowOnFocus);
    }
    public void SetCueBanner(IntPtr handle, string text, bool showOnFocus) {
        if (handle != IntPtr.Zero) {
            SendMessage(handle, EM_SETCUEBANNER, showOnFocus ? 1 : 0, text);
        }
    }
    private const int EM_SETCUEBANNER = 0x1501;
    [DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    private static extern int SendMessage(IntPtr hWnd, int msg, int wParam, string lParam);
}

public class TextBoxInputDesigner : ControlDesigner {
    private readonly string[] RemovedProperties = new[] {
            "AutoSize", "AutoSizeMode", "AutoScroll", "AutoScrollMargin","AutoScrollMinSize",
            "BackgroundImage", "BackgroundImageLayout", "Cursor"
        };
    public TextBoxInputDesigner() { }
    public override void InitializeNewComponent(IDictionary defaultValues) {
        base.InitializeNewComponent(defaultValues);
        var descriptor = TypeDescriptor.GetProperties(Component)["Text"];
        if (descriptor != null && (descriptor.PropertyType == typeof(string))) {
            descriptor.SetValue(Component, string.Empty);
        }
    }
    protected override void PreFilterProperties(IDictionary properties) {
        foreach (string prop in RemovedProperties) {
            properties.Remove(prop);
        }
        base.PreFilterProperties(properties);
    }
}