Hi,
Try this one, In this solution, you can use "PdfStamper" to Save the file, instead of using any other method.
Dim FilePath As String = Server.MapPath("/docs/templates/page_1_cover.pdf")
Dim reader As New PdfReader(FilePath)
Dim newfile As FileStream
newfile = New FileStream(Server.MapPath("/docs/output/go.pdf"), FileMode.Create, FileAccess.Write)
Dim stamper As PdfStamper = New PdfStamper(reader, newfile)
stamper.AcroFields.SetField("APPLICANT NAME", "han")
reader.Close()
stamper.Close()
Note:
In above your Code you didn't specified valid path.
Regards
sarva