You can create orders with in ShipIt manually to do so select
Ship > +New Order
On the destination tab populate the contact details and the address details.
Click the shipping tab
On the shipping tab click the + to add an order item. Fill in the description, SKU, Quantity, Cost, weight, colour, size etc
Under delivery service select the courier service from the drop down and the box or satchel.
Press Save or Print label.