I created this in a tutorial video on how to create script and user properties in Google Apps Script.

Video - Save Script and User Properties

// Kurt Kaiser
// kurtkaiser.us
// All Right Reserved, 2019

var ui = SpreadsheetApp.getUi();
var scriptProperties = PropertiesService.getScriptProperties();
var userProperties = PropertiesService.getUserProperties();

function onOpen(){
  ui.createMenu('Save a Property')
    .addItem('Script - Save Property', 'scriptPrompt')
    .addItem('Script - Show Alert', 'scriptAlert')
   .addSubMenu(ui.createMenu('More Script')
     .addItem('Number', 'scriptTwo')
     .addItem('Mooooo', 'favoriteAnimal'))        
    .addItem('User - Save Property', 'userPrompt')
    .addItem('User - Show Alert', 'userAlert')
  .addItem('Delete a Property', 'deletePrompt')
    .addItem('Delete Everything', 'deleteAll')
    .addItem('Alert Everything', 'alertAllProperties')
  .addToUi();
}

function scriptPrompt(){
  var scriptValue = ui.prompt('Favorite color ' , ui.ButtonSet.OK);
  scriptProperties.setProperty('color', scriptValue.getResponseText());
}

function scriptAlert(){
  ui.alert('Color: ' + scriptProperties.getProperty('color'), ui.ButtonSet.OK)
}

function userPrompt(){
  var userValue = ui.prompt('Favorite food ' , ui.ButtonSet.OK);
  userProperties.setProperty('food', userValue.getResponseText());
}

function userAlert(){
  ui.alert('Food: ' + userProperties.getProperty('food'), ui.ButtonSet.OK)
}

function scriptTwo(){
  var num = ui.prompt('Favorite number ' , ui.ButtonSet.OK);
  scriptProperties.setProperty('num', num.getResponseText());
}

function favoriteAnimal(){
  var cow = ui.prompt('Favorite animal ', ui.ButtonSet.OK_CANCEL);
  scriptProperties.setProperty(cow.getResponseText(), cow.getResponseText());
}

function deletePrompt(){
  var remove = ui.prompt('Enter key of property to delete ' , ui.ButtonSet.OK_CANCEL);
  deleteOneProperty(remove.getResponseText());
}

// ----------- Operations ---------------------------

function deleteAll(){
  scriptProperties.deleteAllProperties();
  userProperties.deleteAllProperties();
}

function alertAllProperties(){
  var stringProperties = '';
  var data = scriptProperties.getProperties();
  for (var key in data){
    stringProperties = stringProperties + 'Key: ' + key + ' Value: ' + data[key] + '\n';
  }
  ui.alert(stringProperties);
}

function alertAllKeys(){
  var stringKeys= '';
  var allKeys = scriptProperties.getKeys()
  Logger.log('allKeys: ' + allKeys);
  for (var key in allKeys){
    stringKeys = stringKeys + 'Key: ' + allKeys[key] + '\n';
  }
  ui.alert(stringKeys);
}

function deleteOneProperty(input){
  Logger.log('Ran delete one: ' + input);
  scriptProperties.deleteProperty(input);
}

function makeMultiple(){
  scriptProperties.setProperties({
    'Boston': 'Massachusetts',
    'Austin': 'Texas',
    'Seattle': 'Washington'
  }, true);
}

function makeArray(){
  var someNames = ['Fred', 1232, 'Juan', [123.33, 666], 'Kayla'];
  scriptProperties.setProperty('someNames', someNames);
}