You can raise or lower a door in a wall using the Elevate tool on the door’s right-click menu. You may, for example, want to lower your garage door if your ground floor sits above the ground.
To raise or lower a door:
Select the door whose elevation you want to edit.
Right-click and select Elevate, or select Edit > Modify Elements > Elevate. The value currently shown in the Elevate dialog is the current elevation of the door above or below the floor level.
In the Elevate dialog, specify the desired elevation of the door base above the floor. You can enter a negative value to move the door down.
Click OK.