Use the script editor with Google Forms

readme.md

CopyPasta for Google Forms

Code.gs

function onOpen() {
  FormApp.getUi()
    .createAddonMenu()
    .addItem('Copy text into form', 'importText')
    .addToUi();
}

function importText() {
  var commentModal = HtmlService
    .createHtmlOutputFromFile('Textbox')
    .setTitle('Import text')
    .setWidth(600)
    .setHeight(300);
    
  FormApp.getUi().showModalDialog(commentModal, "Import Text"); 
}


/**
 * This function takes the text from the modal window and creates either multiple choice questions or short answer
 */
function cpCreator(text) {
  //declare the FormApp service
  var form = FormApp.getActiveForm();
  
  //create an array for all the questions
  //create an array for each question depending on type
  var questions = [];
  var question = [];
  
  
  //use the text argument sent from the text box to determine if it is a short answer or multiple choice
  text.forEach(function(each) {
    //if the element in the array is not empty then add it to the question array
    if(each !== '') {
      question.push(each);
    } 
    //if the element is empty then add the question array to the questions array and delete it to start over
    else {
      questions.push(question);
      question = [];
    }
  });
  
  
  //this loop will create the form items depending on the length of each array inside the questions array
  questions.forEach(function(each) {
    if(each.length > 1) {
      var title = each.shift();
      var mc = form.addMultipleChoiceItem()
      mc.setTitle(title);
      mc.setChoices(each.map(function(e) {return mc.createChoice(e)}));
      
    } else if(each.length === 1) {
      var t = form.addTextItem()
        .setTitle(each[0]);
    }
  });
}

Textbox.html

<link rel="stylesheet" href="https://ssl.gstatic.com/docs/script/css/add-ons1.css">

<div class="block form-group">
  <textarea id="quiz-data" rows="15" style="width: 100%;"></textarea>
  <button type="button" class="create" id="submit-data">Create form</button>
</div>
    
<script>

function submitData() {
  var formData = document.getElementById('quiz-data').value;
  formData = formData.split('\n');
  formData.push('');
  
  google.script.run
    .withSuccessHandler(function(response) {
      google.script.host.close();
    })
    .cpCreator(formData);

}

document.getElementById('submit-data').addEventListener('click', submitData);

</script>