' For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
Using doc As MultiframeImageDocument = Document.Load(Of MultiframeImageDocument)(FilePath)
' Initialize text or image watermark
Dim watermark As New TextWatermark("Test watermark", New Font("Arial", 19))
' Add watermark to the first frame
doc.Frames(0).AddWatermark(watermark)
doc.Save()
End Using