• Push rules:

A rule that triggers another stock move based on the destination location of the original move.  The new move has as source location the destination location of the original move.  

Example: When products arrive manually in the “Input” location, you want to move them to “Stock” with a push rule afterwards.  

So, when a stock move “Supplier → Input” is confirmed, this rule will create another stock move: “Input → Stock”. It allows for 3 modes: automatic (the second operation will be validated automatically), manual (the second operation must be validated manually), manual no step added. (the destination of the first move is replaced instead of creating another stock move.

Push rules should typically only be used on incoming side when a purchase order is created manually and the goods need to be transferred to stock. 

• Pull rules:

Pull rules are not the opposite of push rules! It’s very different as push rules impact moves and pull rules impact needs. (procurements)  It is actually better to call them procurement rules. It is however true that the push rules are applied on the destination location and pull rules on the source location.  

When a stock move is confirmed and its procurement method is 'Advanced: Apply procurement rules', it will create a procurement in the source location for the quantity of the move.  To fulfill this procurement, a procurement rule needs to be applied on this procurement.  There are several types of procurement rules with different results: move products from another location to the source location, purchase to the source location, produce towards the source location.  

A procurement does not need to be created by a stock move however.  A user can create a procurement manually and when we confirm a sale order, Odoo will create a procurement per sale order line in the Customers location.  Actually, this system of procurements, stock moves and procurement rules is used consistently throughout Odoo.  Even in the simplest warehouse configuration, when we run the procurements generated from the sale order, these procurement rules will generate the delivery order.