EFD shows areas for stands and zones in the units your drawing uses. To show square feet instead of square metres, change the drawing's units to feet and inches.
Set the Units to Fractional Feet / Inches, with a precision of 1/16" and a cursor increment of 1'-0".
In Grid & Snaps on the SETTINGS ribbon, set the visible grid to 1'-0" and the snap to 6". See Grid Settings.
Your keys and the meterage report will now show areas in sqft.
NOTE: A plan must use either metres or feet; you can't mix unit types. Metres don't convert exactly to feet and inches, so stand sizes may show odd figures after you switch, and you may need to adjust stands to the size you need.
NOTE: Floorplan Live keys don't show the area figures on screen, but the PDFs downloaded from Floorplan Live are correct.