Warehouse in excise

One manufacturing company need to open a warehouse and sale goods from warehouse.
I have Some Doubts..

1. Excise registration is mandatory for ware house to move goods?

2. when I am moving goods from manufacturing unit to warehouse separate Excise Invoice with duty is required?

3. when i pay the Excise Duty(moving from manufacturing unit or Moving From ware house?)

Pleas give me a Brief note about this.

Thanks..