I am unable to take up TASKS at Mylot.

Oh! I did not know that. My problem is that,I am unable to submit the task itself. For example, I am not able to type in the place where username has to be typed as part of the task.

When you see a task that you want to complete, do you open it, read through the instructions to make sure it's something you can do and then scroll to the bottom to find the orange button that says "accept this task"? If you are able to click the button, it moves the task from the "available" folder to your "in progress" folder. You should only work on the tasks that are in your "in progress" folder. Once they are there, you should be able to put information into the box and then click the "submit" button.