Hi, 

Please refer this blog to know about reordering rules and replenishment in detail:

https://www.cybrosys.com/blog/reordering-rule-and-replenishment-in-odoo-15-inventory

You can also refer video
link:- https://www.youtube.com/watch?v=YaV1drvoDYM

Regards

Please take a look at the Odoo documents. 
https://www.odoo.com/documentation 
Especialy to:  https://www.odoo.com/documentation/16.0/applications/inventory_and_mrp/purchase/products/reordering.html?highlight=reordering

Hi Roger,

Reply: In Odoo, the Reordering Rule is a feature that allows you to automate the process of reordering products when their stock levels fall below a certain threshold.

The Reordering Rule in Odoo works as follows:

1. Defining the minimum stock level: You can define the minimum stock level for each product in the inventory tab of the product form. The minimum stock level is the threshold at which the reordering rule will be triggered.

2. Defining the maximum stock level: You can also define the maximum stock level for each product. The maximum stock level is the threshold at which the system will stop generating purchase or manufacturing orders.

3. Associating a reordering rule: Once you have defined the minimum and maximum stock levels for a product, you can associate a reordering rule with that product. To create a reordering rule, go to the Inventory app and select the "Reordering Rules" menu item. From there, you can create a new reordering rule and associate it with a product and a warehouse.

Regards,

Ksolves Team!