The Item List is where you define all of the service items that your company expends to help support your customers. This includes labor rates, products, parts, and expense items (ie: mileage, airfare, etc).
Work Orders > Item List
An hourly or fixed rate labor charge. The QuickBooks equivalent is 'Services'.
A product, part or equipment item that you sell to your customers. The QuickBooks equivalent is 'Inventory & Non-Inventory Parts'.
A non-labor, non-product charge to your customer (e.g. travel, rental fees, etc). The QuickBooks equivalent is 'Other Charges'.
Using Items on Work Orders
When you perform work on a job, you'll use BlueFolder to add the appropriate items to the Work Order for that job. When an item is added to a Work Order, a copy of that item is forever stored with the Work Order. This copy of the item can be modified in the Work Order without changing the Item List copy of the item. The item in the Work Order is really a separate copy of the item that retains it's attributes (such as price, cost, description, etc.) as they existed at the time the item was added to the Work Order.
BlueFolder does it this way in order to preserve historical accuracy. For example, if you pull up a Work Order from last year, the labor rates will still be shown as they were at the time because that is what you charged to the customer at that time.
Read more about importing items from Quickbooks or any text file or spreadsheet.