Creation signature field + appearance Dim sig As Field = _pdfdoc.FieldCreate("sig" & numberPage.ToString, Field.Type.e_signature) Dim annotTypeWidget As pdftron.PDF.Annots.Widget = pdftron.PDF.Annots.Widget.Create(_pdfdoc.GetSDFDoc, New Rect(bbox.x1, bbox.y1 + 10, bbox.x1 + 150, bbox.y1 + 70), sig) annotTypeWidget.SetPage(itrCurrent) annotTypeWidget.SetContentsnumberPage.ToString()) annotTypeWidget.SetAppearance(CreateSignatureAppearance(_pdfdoc)) Delete field Dim contents As String = "" Dim type As Annot.Type Dim ann As Annot For j As Integer = (_pdfdoc.GetPage(1).GetNumAnnots - 1) To 0 Step -1 'If _pdfdoc.GetPage(1).GetAnnot(j).IsValid() Then ann = _pdfdoc.GetPage(1).GetAnnot(j) type = ann.GetType If (type = Annot.Type.e_Widget) Then contents = Path.GetFileName(ann.GetContents) If contents = "1") Then _pdfdoc.GetPage(1).AnnotRemove(ann) ann.GetSDFObj().Erase("AP") _pdfview.SetDoc(_pdfdoc) End If End If Next Check existing signature filed If (_pdfdoc.HasSignatures) ... ... end if