The sample demonstrates how to replace one word to another in a Word document.

private void button1_Click(object sender, EventArgs e)
{
    //Create word document
    Document document = new Document();
    document.LoadFromFile(@"..\..\..\..\..\..\Data\FindAndReplace.doc");

    //Replace text
    document.Replace(this.textBox1.Text, this.textBox2.Text,true,true);

    //Save doc file.
    document.SaveToFile("Sample.doc", FileFormat.Doc);

    //Launching the MS Word file.
    WordDocViewer("Sample.doc");
}

private void WordDocViewer(string fileName)
{
    try
    {
        System.Diagnostics.Process.Start(fileName);
    }
    catch { }
}

 Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles button1.Click
	'Create word document
	Dim document_Renamed As New Document()
	document_Renamed.LoadFromFile("..\..\..\..\..\..\Data\FindAndReplace.doc")

	'Replace text
	document_Renamed.Replace(Me.textBox1.Text, Me.textBox2.Text,True,True)

	'Save doc file.
	document_Renamed.SaveToFile("Sample.doc", FileFormat.Doc)

	'Launching the MS Word file.
	WordDocViewer("Sample.doc")
End Sub

Private Sub WordDocViewer(ByVal fileName As String)
	Try
		Process.Start(fileName)
	Catch
	End Try
End Sub