How do I link a single Contact to multiple Organizations in Vtiger CRM?

By default, Vtiger CRM follows a one-to-many relationship, where a single Organization can have multiple Contacts but each Contact can belong to only one Organization.
If you want a Contact to appear under multiple Organizations, you must change this to a many-to-many relationship. Follow these steps to enable this:

1. Log in to the CRM.
2. Click the User Profile in the top-right corner of the screen.
3. Go to Settings. The Settings page opens.
4.  Go to Module Management > Module Layouts & Fields. The Module Layouts & Fields page opens.
5. Select Organizations from the Select Module drop-down.
6. Click the Relationships tab.
7. Change the current relationship type from One-to-Many to Many-to-Many.

Once saved, you will be able to assign one Contact to multiple Organizations.