Dear Harsh,
Maybe you can try the below observations for your issue
a.) Basically system will create customer project with sales integration type. Basically there is no option to select "work description mandatory in project type" BC fine tuning activity. But like Ms. sahalya mentioned you can maintain this is in template of a project type.
b.) you will be able to select a template for a project type when you create a project from sales order.
c.) However when you create a project from sales order it would most probably in "planning" status and at this point you can change the "work description" required at header level. Any further addition of the sub-task directly in project will have this setting by default.
d.) If all your task are created from sales order, then you will have to manually change as mentioned above.
c.) you can also create project and then assign it sales order as well by following sahalya advice.
e.) Or you can check with partner to add this "work description" required to the BC activity.
Regards
Leo