How to connect multiple accounts to single contact in Salesforce?

Setups to connect contacts to multiple accounts is quite easy and quick. Following are the steps to be followed:

1. Go to Setup, enter Account Settings in the Quick Find box, then choose Account Settings.
2. In the Account Settings, Enable the checkbox ‘Allow users to relate a contact to multiple accounts‘ to true.
3. Once you enable the above checkbox, a message will display quoting ‘Contacts to Multiple Accounts has been enabled for your organization‘.
4. Now from setup enter Account in the Quick Find box, click Page Layouts.
5. Select the appropriate page layout, click Edit.
6. Select Related Lists.
7. Drag Related Contacts onto the page layout and click save.

Here comes creating and editing relationships between Contacts and Accounts.

1. Open an Account record and Go to Related Contacts related list for creating and editing relationships. To create a new relationship click Add Relationship.
2. To Edit an existing relationship, click on Edit Rel (in Salesforce Classic) or Edit Relationship (in Lightning Experience).
3. On Click of Add Relationship, a form will open, fill all the required information and save the changes.