On this page of the Genshin Impact gyude you will find out if you can co-op with other players, even if they play on different platforms.
Yes, there is crossplay in Genshin Impact, which means you can play with players from different platforms (PC, PS4, Android, and iOS). However, in order to unlock crossplay, you must earn the required Adventure Rank and complete the missions needed to do so. Once you do that, the co-op becomes possible for you and others. However, be sure that your party has the right level, if it's too low, then you won't be able to explore certain dungeons.