Ask customer for additional information

From Shopify Wiki

When you update the content of a cart or click the checkout button on a standard Shopify cart.liquid page, Shopify looks for two special parameters called note and attributes to include with the order.

Note

Imagine that you’re running a gift shop and you want to ask your customers for a note to be included in the package.

To get that functionality, add the following html/liquid code to your cart.liquid after <form> and before the </form> tag:

<p>
  <label for="note">Gift note:</label><br/>
  <textarea name="note" id="note" rows="3" cols="60">{{cart.note}}</textarea>
</p>

After placed and paid, this order will display the note in the Shopify admin.

Note Attributes

Note Attributes let you attach arbitrary values to an order, making them useful for creating more complex forms with checkboxes, drop-downs or even hidden fields which just attach the browser version or operating system of the client to the order.

Create them by using the name attribute on input elements:

 <input type="checkbox" name="attributes[wrapping]" value="yes" />

Note that note attributes may not be nested, so attributes[wrapping][fabric] or attributes[wrapping][style] will not work as expected. (The notes attributes are flattened to a single level.)

As an example, let’s ask the customer if they want their gift wrapped:

<p>
  <input type="checkbox" name="attributes[wrapping]" value="yes" {% if cart.attributes.wrapping %} checked="checked"{% endif %} />
  <label for="wrapping">Please wrap the products in this order:</label>
</p>

This order, after it’s placed and paid, will display the following note in the Shopify admin:

You can add as many attributes as you like, but each attributes[name] must be unique.

Another Example for Attach Notes

A shop sells conference tickets (the products), with attendance times (e.g. 'Saturday', 'Sunday', 'Entire Conference') stored as variants.

{% for item in cart.items %}

  {% for i in (1..item.quantity) %}
 
  <h4>{{ item.variant.title }}</h4>
  
  <dl>
    <dt>Name you wish to appear on your badge:</dt>
    <dd><input type="text" name="attributes[{{ item.variant.title }} Attendee Badge]" value="" id="badge"></dd>
  </dl>

  {% endfor %}

{% endfor %}