From any task list, open the task to delete by clicking on its Summary and click the “Delete this task” option located in the right pane.
Project Managers and Administrators may also delete multiple tasks in a single operation in the project’s task list page. The tasks to be deleted must first be checked and the option to delete the checked tasks is located in the “Actions on checked tasks” section, in the right pane.
Normal users must have sufficient “Edit Task Level” access rights on the associated project to perform this operation.