Program.cs

using Syncfusion.DocIO;
using Syncfusion.DocIO.DLS;


//Register Syncfusion license
Syncfusion.Licensing.SyncfusionLicenseProvider.RegisterLicense("Mgo+DSMBMAY9C3t2UlhhQlNHfV5DQmBWfFN0QXNYfVRwdF9GYEwgOX1dQl9nSXZTc0VlWndfcXNSQWc=");

using (FileStream inputFileStream = new FileStream(Path.GetFullPath("Data/Template.docx"), FileMode.Open, FileAccess.ReadWrite))
{
    // Open the input Word document
    using (WordDocument document = new WordDocument(inputFileStream, FormatType.Docx))
    {
        // Find a table with its alternate text (Title property).
        WTable table = document.FindItemByProperty(EntityType.Table, "Title", "DataTable") as WTable;
        // Check if the table exists.
        if (table != null)
        {
            // Add a new row to the table.
            table.AddRow();
        }

        using (FileStream outputFileStream = new FileStream(Path.GetFullPath("Output/Result.docx"), FileMode.Create, FileAccess.Write))
        {
            // Save the modified document to the output file stream.
            document.Save(outputFileStream, FormatType.Docx);
        }
    }
}