Purchase Order - A purchase orders represents items that you purchase from a vendor. It may include materials which are reimbursable, labor items, equipment items, expense items, or even discount items. You can watch a video to learn more about how to use purchase orders in SingleOps here.
Expenses - (also called job expenses) are a special type of purchase order with some added functionality. They can be added from the job's completion page:
or they can be added from the Create New Purchase Order page:
Expenses added from the job completion page, along with purchase orders created within the job's visit(s)contribute to job costing within SingleOps. Purchase orders created and associated to the job do not affect the job costing inside SingleOps - although they sync to QuickBooks in exactly the same manner.
Quickbooks Bill - Bills are the QuickBooks equivalent to SingleOps' purchase orders, and thus to SingleOps' expenses. You can, however, configure purchase orders and expenses in SingleOps to not sync to QuickBooks if you so desire.
Purchase orders associated to a job, purchase orders associated to a visit, and job expenses will all sync to QuickBooks once the job has been approved.
Purchase orders not associated to a job or a visit will sync to QuickBooks as soon as the purchase order has been approved.
NOTE: Both of the above statements are predicated on the included items being marked as 'Is Reimbursable' on the items page.