In general, a Purchase Order is a legally standing financial document that is used to manage the purchasing of products and services from external suppliers/vendors.
In almost all scenarios, a Purchase Order must pass through an approval process before the transactions contained in it can be executed. This arrangement helps management keep a track on expenses.
In the Mr.Albert POR product, the terms Purchase Order and Purchase Order Requests are used interchangeably and both the terms refer to practically the same concept. If needed, a Purchase Order Request (POR) can be considered as the 'state' of a Purchase Order until it is approved. That is, a Purchase Order becomes a Purchase Order when it is approved and until then it remains a Purchase Order Request. As mentioned, the subtle difference between the two terms is immaterial in the context of Mr.Albert POR product.
Each POR is linked to a Budget and a Vendor.
A Budget is essentially an expense category with a specified total amount available for spending on Purchase Orders created under it. Read the reference article on Budgets to know more about them.
A Vendor is an external entity (an individual or a business) from whom goods and/or services are purchased by your company. Read the reference article on Vendors to know more about them.