As well as being able to add Tasks to your Contacts, you can add Tasks directly to Opportunities and Cases to plan out your sales, projects and events. These are added in exactly the same way as you add them to Contacts by clicking the Add Task button at the top-right of the page. The newly created Task will be linked to the Opportunity or Case, rather than the Contact and will be visible when viewing that record.
You can add a predefined list of Tasks to your Cases and Opportunities at once using Tracks where each task is completed in a certain order. This is useful when you follow a repeatable workflow for your sales and projects.
Tracks are predefined by an account administrator. Learn more about using Tracks