Marketing Opportunities are available in Salesforce Classic.
Marketing Opportunities Screen
Can only see Marketing Opportunities that are:
Assigned to the current user's Staff record.
Due in the past (can't see future Marketing Opportunities) or Marketing Opportunities that do not have a due date.
Have not been completed.
Only the first 200 Marketing Opportunities that match the above criteria will be shown.
Marketing Opportunities can only be created from a Prospect.
Marketing Opportunities are sorted by their due date where the most recently due are towards the top.
Marketing Opportunities Tab on Prospect Screen
Can see all Marketing Opportunities that are related to the Prospect.
If want to restrict user to only see Marketing Opportunities assigned to the current user, recommend to setup the appropriate Sharing Rule in Salesforce.
Marketing Opportunities that are not completed are at the top of the list and then sorted by Completed Date.
When the Completed Date is set, the Completed By field will be set to the current signed in users Staff record.