Query related to Userform

[Excel]

Hello Everyone, 

I have written VBA code in Append Text to Row Button :

I want the vba code in the user form to be able to loop through a selected range (A4:A14) ,in which the code starts from row A4 but i dont know how to make the code more dynamic so that once someone types text in the textbox and appends the text to the new rows , its offsets to the row underneath it.

Please help. 

Here is a attached file.

[#2]

@Excel 

I made the text box multi-line and set it to create a new line when you press Enter.

Private Sub CommandButton1_Click()
    Dim i As Variant
    Dim rowcounter As Long
    rowcounter = Cells(Rows.Count, 1).End(xlUp).Row
    For Each i In Split(Me.TextBox1, vbCrLf)
        rowcounter = rowcounter + 1
        Cells(rowcounter, 1).Value = i
    Next i
    Me.TextBox1 = ""
End Sub