Salesforce: Opportunity Contact Roles are Added by Default

When Opportunity Contact Roles are Added by Default?

• From a Contact Record: When users create a new opportunity directly from the Related List on a Contact record, that contact is added as a contact role.
• During Lead Conversion: When a Lead is converted into an Opportunity, Salesforce automatically links the converted Contact to the new Opportunity.

As above, this only happened during Opportunity creation, and not during Opportunity edit.

What is the Role and Primary?

• Role = blank
• Primary = Yes

Automation

Salesforce administrators/developers can create Flows or Apex Triggers to create contact roles automatically based on custom criteria when an opportunity is created or edited.