The following code snippet demonstrates how to convert a html file into PDF format using iText library in VB.NET.
[VB.NET CODE STARTS]

First we need to add reference to iTextSharp library.

' Add references
 
Imports System.IO
Imports iTextSharp.text
Imports iTextSharp.text.pdf

' Read html file to a string
 Dim sr As StreamReader = New StreamReader("YOUR HTML FILE PATH WIIH NAME")
 Dim line As String
 
 line = sr.ReadToEnd
 sr.Close()
 
' Code to convert to pdf
  Dim doc As New Document(PageSize.LETTER, 80, 50, 30, 65)
  Dim fsNew As New StringReader(line)
  Dim document As New Document(PageSize.A4, 80, 50, 30, 65)
 
        Using fs As New FileStream("YOUR PDF FILE PATH WITH NAME", FileMode.Create)
            PdfWriter.GetInstance(document, fs)
            Using stringReader As New StringReader(line)
                Dim parsedList As System.Collections.Generic.List(Of IElement) = html.simpleparser.HTMLWorker.ParseToList(stringReader, Nothing)
                document.Open()
                ' parse each html object and add it to the pdf document
                For Each item As Object In parsedList
                    document.Add(DirectCast(item, IElement))
                Next
 
                document.Close()
 
            End Using
 
        End Using

[VB.NET CODE ENDS]