The way this can be implemented varies based on your actual needs.

Generally speaking, you can define who has access to what by the means of

• Groups
• Access Rights
• Record Rules

You can check out how such, for example Record Rules, are defined by enabling the Developer Mode (see https://www.odoo.com/documentation/18.0/applications/general/developer_mode.html) and the n navigate to

Settings -> Technical -> Record Rules

To get you going, you may want to start with this video tutorial: https://www.odoo.com/slides/slide/10139

Further details can also be found in the docs here: https://www.odoo.com/documentation/18.0/applications/general/users/access_rights.html

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