Here is a sample .csv in the Shopify format for your reference. Don't worry if you don't have all that information though! The  fields that we will want from your other e-commerce provider are: customer name, customer address, customer email, order number, order total, SKU, item name, item description. Anything else is a bonus that will help us to set up your orders with as much information as possible, but as long as you have those fields we will be able to import successfully.