According to the Fiat UK website all models (Easy, Easy Plus and Lounge) have ESP (Electronic Stability Programme) & MSR, ASR & Hillholder
If if follows all other similary equipped Fiat models then Hillholder can not be turned off and is enabled as standard.
Find yourself a hill/slope to stop on. Come to a stop on the brake pedal and then release the brake pedal. Car should remain stationary for a couple of seconds (+) and then the brakes will be released and it will roll back.