The space suit can be found in the EVA storage section of the station. It is often found with the Space Helmet, a Medical Mask, latex gloves, a Jetpack, white shoes, and a white jumpsuit.
The space suit will protect your body from depressurised zones, such as space or an area of the station where there are several hull breaches. You should generally equip a space helmet whilst using a space suit, to ensure full coverage, and a jetpack is a good idea if you plan to be moving around outside the station. Also, this suit does not protect from fire.