For the Intro Program you wear anything sutiable to exercise in. Barefeet are fine but non marking shoes (on the carpet) are better to get you accustomed to doing techniques with footwear. Students who have joined up wear the Krav Maga uniform (MMA style black pants with Krav Maga T-shirt).
However, as this is a street defence system, there will be occasions when alternate forms of dress will be required, e.g. wearing jackets or overcoats so students become accustomed to training in attire worn in winter. The instructor will advise this prior to the time required.