The Hidden Palace of Zhou Formula is an important Abyssal Domain in Genshin Impact, but it is not one that you can just walk into. You will need to solve a bit of a puzzle to be able to get inside. To enter, you will need to have an Adventure Rank of 30, and a party rank of 59.
You can find the Hidden Palace of Zhou Forumla near Wuwang Hill in Liyue, to the southwest of Dawn Winery.
To gain access to the Abyssal Domain, you will need a party member that can do Pyro, and another that can do Geo. The Pyro character will need to light torches, while the Geo character will need to interact with a Geo monolith in front of the door.
The first torch can be found right beside the Geo monolith, just hit it with any Pyro ability to light it. The second can be found inside a wind barrier. You will need to climb up above the barrier, then glider down into it to be able to light the torch. When you light it, the barrier will vanish.
The third torch can actually be found up the cliff face a little bit, climb up the ladder on the cliff to find it near a fence, and some Hilichurls. From there, go right towards the shrine with the blue floating lights, jump across the gap, and you will find the last torch you need to light.
When all of them have been lit, go back and hit the Geo monolith with a Geo ability to uncovered the entrance to the Hidden Palace of Zhou Formula. For the best chance of success in this Abyssal Domain, you will want to bring at least one Cryo character in your party.