There’s no Tasks tab in Salesforce Classic beyond the My Tasks list on the Home page.
In Lightning Experience Tasks have their own tab, so they are easy to find.
Click the Tasks tab, or click View All from the My Tasks list on the Lightning Experience Home page.
Keep Your To-Dos Up to Date
Another great aspect of the task list is that while you see the list on the left, expanded details appear to the right for whichever task you have selected.
Click a task on the left, and see that info on the right.
Lightning Experience includes several quick actions in the detail view—just click the dropdown—that make it efficient to update tasks. You can change status, change priority, edit, and delete. Or, click the checkbox to mark the task complete. Of course, tasks are also shown in the activity timeline for the record you are looking at, and you can edit them there too.