Insert today's date into a Google doc, using a custom macro (Utilities/Insert Today's Date)

todays-date.gs

/**
 * The onOpen function runs automatically when the Google Docs document is
 * opened. Use it to add custom menus to Google Docs that allow the user to run
 * custom scripts. For more information, please consult the following two
 * resources.
 *
 * Extending Google Docs developer guide:
 *     https://developers.google.com/apps-script/guides/docs
 *
 * Document service reference documentation:
 *     https://developers.google.com/apps-script/reference/document/
 */
function onOpen() {
  // Add a menu with some items, some separators, and a sub-menu.
  DocumentApp.getUi().createMenu('Utilities')
      .addItem('Insert Today\'s Date', 'insertDate')
      .addToUi();
}

/**
 * Inserts the date at the current cursor location.
 */
function insertDate() {
  var cursor = DocumentApp.getActiveDocument().getCursor();

  if (cursor) {
    // Attempt to insert text at the cursor position. If insertion returns null,
    // then the cursor's containing element doesn't allow text insertions.
    // Available date formatting options: http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html
    var date = Utilities.formatDate(new Date(), "EST", "EEEE, MMM d, YYYY"); // Tue, Nov 1, 2016
    var element = cursor.insertText(date);
    
    if ( ! element) {
      DocumentApp.getUi().alert('Cannot insert date at this cursor location. Please move cursor and try again.');
    }
  } else {
    DocumentApp.getUi().alert('Cannot find a cursor in the current document.');
  }
}