' For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
Using doc As Document = Document.Load(Utilities.MapSourceFilePath(DocFilePath))
Dim font As New Font("Times New Roman", 8)
Dim watermark As New TextWatermark("Test watermark", font)
' Set watermark coordinates
watermark.X = 10
watermark.Y = 20
' Set watermark size
watermark.Width = 100
watermark.Height = 40
doc.AddWatermark(watermark)
doc.Save()
End Using