You can find out information about Creeps in the Xenopedia found on the main map screen by pressing the settings buttons on the upper left hand corner and selecting the Alien Creep head button.
If you tap a Creep mid-game, you’ll get a small information panel at the bottom of the screen. This will give you general information about the Creep, including what type of defence they have. If a Shield icon is present Lasers will do full damage whilst if a Body Armour icon is view-able they’ll resist Laser damage.
Only enemies you have encountered will show up in this list. Keep playing through the campaign to encounter new Creeps with different abilities.