How to run scripts on multiple sheets of Google Sheets

Here's my code:

function transferNotes() {
  // Get notes (not comments) from the source spreadsheet
  var sourceSpreadheet = SpreadsheetApp.openById('1GdoTw3KxQO03xp5CiKX9VIJMZQfPMPbGdCa_PvnQaoI');
  var sourceTab = sourceSpreadheet.getSheetByName('SpA')
  var sourceRange = sourceTab.getRange('D2:D2000');
  var notes = sourceRange.getNotes();

  // Post the notes to the target spreadsheet
  var targetSpreadheet = SpreadsheetApp.openById('1YApnQ64OYFOYKQrefuxJ0gwpchAKRatWpJsSNLeevO4');
  var targetTab = targetSpreadheet.getSheetByName('SpB');
  var targetRange = targetTab.getRange('D2:D2000');
  targetRange.setNotes(notes); 
}

I want to run this code on multiple sheets at once and automatically update notes in real time without having to run the script every time to update it. Help me.