Add order metafield to customer profile

Checkout Blocks allows you to add custom fields to checkout for example, the following birthday dob (date of birth) input:

• Ensure the custom field is saved as an order metafield:

• Setup a custom Shopify Flow workflow which will run on order placement. You can download one we've already created. It will check for the existence of your order metafield and then save the value as a customer metafield:
  

• Enable this workflow and place a test order. You should see the birthday show up on your test customer profile within the Shopify admin within a minute of order placement.
  
• If you don't see the metafield on the customer:
  • Double check the Checkout Blocks custom form key with the values specified in the Flow workflow:

• Alternatively, you may have to create a customer metafield definition for it to show on the customer detail page within the Shopify admin: