Paul

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({  
  firstName: '',
      
  resume: '',
  
  emailWithOffers: false,
    
  formPayload: null,
  
  actions: {
  	onFormSubmit() {
      this.set('formPayload', JSON.stringify(this.getProperties('firstName', 'resume', 'emailWithOffers')));
    }
  }
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

input[type="file"] {
  position: absolute;
  left: -9999px;
  top: -9999px;
}

.file-input-label {
  color: blue;
  text-decoration: underline;
}

templates.application.hbs

<h1>Welcome to my ember website! Join us!</h1>
<br>

<form onsubmit={{action "onFormSubmit"}}>

  <fieldset>  
    <legend>Who are you? (Required)</legend>
    <label for="first-name">First name</label>
    <br/>
    <input
      id="first-name"
      type="text" 
      oninput={{action (mut firstName) value="target.value"}}
      required
    >
		<br/>
    <label for="last-name">Last name</label>
    <br/>
    <input
      id="last-name"
      type="text"
      required
    >
  </fieldset>

  
  
  
  
  <fieldset>
    <legend>Anything else?</legend>
    <label for="file" class="file-input-label">Upload a resume</label>
    <input
      id="file"
      type="file"
      onchange={{action (mut resume) value="target.value"}}
    >
    <span>{{resume}}</span>
		<br/>
    <input
      id="checkbox"
      type="checkbox"
      onchange={{action (mut emailWithOffers) value="target.checked"}}
    >
    <label for="checkbox">Email me with offers</label>
  </fieldset>
  
  <br/>
  <button type="submit">Submit</button>
</form>


{{formPayload}}
<br>
<br>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}