From the Customer Dashboard, visit the Projects tab by clicking on the Projects button at the top menu
Click on the New Task button on the right side of the project panel
insert the task details and attach any document related to the task then save it
Note: if you cannot see the New Task button because the project is completed or closed, you can do the following
From the Customer Dashboard, visit the Support tab by clicking on the Support button at the top menu
Click on Open Ticket and insert all the details and attach any document needed then submit it