You can create new incidents or link existing incidents to the activity through the Incident section of the form. To link an existing incident to the activity, begin typing keywords in the textbox below the incident table, then click an incident to select it. 
Searching for an existing record to link to an activity
Linking an activity to an incident is not the same as escalating the current activity to an incident. For more information on escalating, see the Escalate an Activity article.
To review the incident's details, click any data in the table (e.g., incident name). 
The Linked to Incident table.