There are four ways to delete a task.
1) From the Tasks tab, find the task you want to delete. Swipe your finger over the task that you want to delete from the right to the left. Tap the red [Delete] button.
2) From the Tasks tab, on the Tasks screen, tap the [Edit] button in the top right. Tap on the [-] button next to the task you want to delete. Tap the Delete button.
3) From the Task Details screen, tap the garbage can button in the top right.
4) If the task is associated with a vendor, you can also delete the task from the Vendor's task list. Go to the Vendor who has the task. Tap the All Tasks section. From the Vendor's Task screen, swipe over the task so that the [Delete] button appears. Then tap the red [Delete] button.