Hi Hari,

The option to select multiple companies simultaneously in Odoo serves several important purposes:

1. Consolidated reporting: It allows users to generate reports and analyze data across multiple companies within the same organization, providing a holistic view of the business.
2. Shared operations: For organizations with multiple legal entities but shared operations, this feature enables users to work across companies without constantly switching contexts.
3. Efficiency: Users who have responsibilities spanning multiple companies can perform tasks more efficiently without needing to log in and out of different company accounts.
4. Data comparison: It facilitates easy comparison of data between different companies in the organization.
5. Centralized management: For group administrators or managers overseeing multiple entities, this feature allows for centralized control and management.
6. Intercompany transactions: It simplifies the process of handling intercompany transactions and reconciliations.

This feature is particularly useful for larger organizations, holding companies, or businesses with complex corporate structures. However, it's important to note that proper access rights and data segregation must be set up to ensure data integrity and security across companies.

https://www.odoo.com/documentation/17.0/applications/general/multi_company.html

https://www.odoo.com/forum/help-1/odoo-16-enterprise-multi-company-221516

Thanks.