To duplicate a task :
Click on the task to duplicate (1)
From the details pane, click the three vertical points (2)
Click on Duplicate Task (3)
A window opens:
The name of the duplicated task is taken again, you can modify it if necessary (4)
If necessary, select the users for whom a copy is to be created, a duplicate will be directly assigned to them (5).
Check the items in the details pane that need to be repeated (6)
Click on Duplicate (7)
Info: You can also duplicate a task in a meeting as well as in your templates and checklists.