How long has the tank been running? If your levels are good (no ammonia, no nitrite, low nitrate), then you should be ready for some beginner corals. A lot of people start out with softies since many of them are easy, but I prefer stony corals and started with LPS like brains and favias. It really depends on what you like.
I wouldn't start out with SPS, but most soft corals and LPS are beginner friendly. Start off with cheaper things you like and avoid expensive small frags - the less you get for the money, the more delicate it tends to be. Better to explore those options once you have experience under your belt.