sheets.mergedCells Array

A range of cells that will be merged into one. The value of the first cell in the range will be displayed in the new merged cell.

<script>
  var workbook = new kendo.ooxml.Workbook({
    sheets: [{
      mergedCells: ["A1:D1"],
      rows: [
        { cells: [ { value: "Document Title" }  ] },
        { cells: [ { value: 22 }, { value: 33 }, { value: 44 }, {value: 55}  ] }
      ]
    }]
  });

workbook.toDataURLAsync().then(function(dataURL) {
  kendo.saveAs({
    dataURI: dataURL,
    fileName: "Test.xlsx"
  });
});
</script>