Google Sheets Function to update time

update_time

function update_time() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var ss = sheet.getSheetByName('Sheet1');
  var formattedDate = Utilities.formatDate(new Date(), "UTC", "MM-dd-yyyy HH:mm:ss");
  var merge_range = ss.getRange(3,3,3,3).merge().setHorizontalAlignment("center").setVerticalAlignment("center").setFontWeight("bold").setBorder(true,true,true,true,null,null,"black",SpreadsheetApp.BorderStyle.SOLID_MEDIUM).setFontSize(25);
  var input_range = ss.getRange(3,3).setValue(formattedDate);
}