function onOpen() {
  const ui = SpreadsheetApp.getUi();
  ui.createMenu('Appreciation')
      .addItem('Create certificates', 'createCertificates')
      .addSeparator()
      .addItem('Send certificates', 'sendCertificates')
      .addToUi();
}
Creates a custom menu "Appreciation" in the spreadsheet
with drop-down options to create and send certificates