Shared Activities is enabled from Activity Settings in Setup. It is a single checkbox, but it is treated as a one way change, so confirm the timing and the consequences before you save. You need a profile with the Customize Application permission.
- Open Activity Settings
From Setup, type Activity Settings in the Quick Find box and select Activity Settings.
- Select the option
Check the box labeled Allow users to relate multiple contacts to events and tasks.
- Save and let it process
Click Submit. Salesforce processes existing activities in the background, usually within one to two hours but sometimes up to 48 hours.
- Add the related list
On Contact, Task, and Event page layouts, surface the related contacts list so reps can add and view attendees.
- Confirm reporting
Use the Activities with Contacts report type to check that activities now show every related contact, not just the primary.
The single setting that turns Shared Activities on across the org. Enabling it is effectively permanent.
The contact shown in the activity Name field. Deleting it promotes the next contact on the related list to primary.
Up to 50 contacts and 1 lead can be related to one task or event.
- Disabling the feature on an active org permanently drops every related contact except the primary one. Contact Salesforce Support first.
- TaskRelation and EventRelation do not support Apex triggers, workflow, or validation rules once Shared Activities is on. Plan automation around the parent Task or Event.
- You cannot relate multiple contacts to recurring tasks.
- Processing after enablement can take up to 48 hours, so schedule the change during a quiet window.