Footings are not included in your deck by default, but you can display them instantly by editing deck properties. You can also choose the footing material you want to use.
To create footings under deck posts:
Select the deck by clicking on one of its edges.
Right-click and select Properties, or select Edit > Modify Elements > Properties.
On the Support property page, check the Include Footings check box in the Supports area.
Click the Select button next to the Include Footings edit box, then select the desired footing type from the catalog.
To edit the properties of the currently selected footing type, click the Edit button, then make the desired changes in the Mono Footings dialog.
Click OK.