title: How to add data into a Merge Field
body: <p>I would like to automate printing invoices from a Word Template. I think I have the logic down but I just don't know the right way of coding it. Here is my current code</p>
  
  <pre><code>Selection wrdSelection;
  MailMerge wrdMailMerge;
  MailMergeFields wrdMergeFields;
  Microsoft.Office.Interop.Word.Application wordApp = new Microsoft.Office.Interop.Word.Application();
  Document wrdDoc = new Document();
  wordApp.Visible = false;
  wrdSelection = wordApp.Selection;
  
  object oMissing = System.Reflection.Missing.Value;
  
  // PUT MY EXISTING TEMPLATE FILE INTO WORD DOCUMENT
  wrdDoc = wordApp.Documents.Add(Properties.Resources.invoiceTemp,oMissing,oMissing, oMissing);
  // RETREIVE MAIL MERGE PROPERTIES FROM THE DOCUMENT IN HOPES OF UTILIZING IT
  
  wrdMailMerge = wrdDoc.MailMerge;
  wrdDoc.Select();
  wrdMergeFields = wrdMailMerge.Fields;
  </code></pre>
  
  <p>If it would help, here are the Merge Fields that I have on my template:</p>
  
  <p><code>date_issued</code>, <code>month_covered</code>, <code>invoiceNo</code>, <code>tuition</code>, <code>lunchFee</code>, <code>discount</code>, <code>studentNo</code>, <code>studentName</code>, <code>amountDue</code>, <code>amountPaid</code>, <code>balance</code>, <code>penalty</code>, <code>status</code></p>
  
  <p>Now, how do I add data that I retrieve using my Application into the document which gets all the properties from the template?</p>