Hi,
You can create each branch or store within Odoo as a distinct company if you're managing many branches or stores. However, if the branches or stores share resources like inventory, clients, or suppliers, this technique might not be acceptable. In that instance, it could be better to create one company and manage all of the branches or stores using built-in features of Odoo like locations and warehouses different branches or stores.
Odoo is a very customizable and extendable system, and third-party modules can frequently provide additional features that aren't always present in the base product. If you're wondering why such a fundamental feature isn't pre-installed in Odoo, it's possible that the developers gave other features or use cases a higher priority. On the basis of user feedback and demand, the developers might also decide to include this functionality in a future edition.
You can use this module for multi branches purposes
https://apps.odoo.com/apps/modules/16.0/multi_branch_base/
Regards