title: How to add a metafield to a customer in Shopify
body: <p>I'm creating a signup form on my Shopify store, for customers. I'm willing to have them enter their basic credentials (email) plus additional info. I'd like to have that additional info stored in the customer's metafields.</p>
  
  <p>I've seen here:  <a href="http://docs.shopify.com/manual/configuration/store-customization/capture-additional-information-in-the-account-registration-form" rel="nofollow">http://docs.shopify.com/manual/configuration/store-customization/capture-additional-information-in-the-account-registration-form</a>    I can ask customers for additional information in the form of notes, but found no path to insert metafields.</p>
  
  <p>I think this is possible, but I don't know how I could do.</p>
  
  <p>Could someone help me, please?</p>