When creating a sim in The Sims Mobile, you have the Style section at your disposal. Within it, you can choose hairstyles, headwear, clothes, makeup, and accessories. However, there are not many available at the beginning. You can buy additional items during the game. Most of them have to be unlocked by gaining a given experienced level. You pay for these accessories with simoleons, simcash, and coupons.
You can only choose your day-to-day clothes.