To clone a task, find the task in a list (for example in "My tasks" or "All tasks"), and click on the three dots on the right hand side of the task row. Then select "Clone" from the list of options.
If the original task had any completed steps, uploaded files, added text or comments these will not be transferred over to the cloned task.
Note: Tasks created from templates cannot be cloned. In this case, to create a copy of the task you can create a new one from the template.