There is a button switch in front the shifter to turn it off. You will have to turn it off every time you start the vehicle. Or you can order this:
https://www.autostopeliminator.com/store/c13/auto-stop-start-disable-ford-ecosport-2018
https://www.autostopeliminator.com/store/c13/auto-stop-start-disable-ford-ecosport-2018