My name is Erin and I am a Guru here at Shopify. Thanks for reaching out!
When it comes to Drop shipping, we have an awesome feature in our Admin that will coordinate your products/orders with specific drop shippers :)
In your store shipping settings you can add fulfillment companies by name and email, you will then associate your products with that supplier in your Product page. When a customer purchases that product, your fulfillment company will receive an email with the order and then ship to your customer.
As you move forward with incorporating more suppliers and products, you will just continue to associate the product with the Drop shipper in your Fulfillment settings :)
Have a great day!