In case you missed it earlier, Ubisoft has decided that it will remove Anno 1800 from Steam and make it available only on its own Uplay and Epic's Games Store. It will still honor all existing pre-orders of the game on Steam and keep it available for pre-order over at Valve's platform but will remove it after it becomes available on April 16th.
According to details provided over at Epic's Game Store, you'll need at least an Intel Core i5-4460 or AMD Ryzen 3 1200, 8GB of RAM, and either an Nvidia GTX 670 or AMD R9 270X in order to run the game at 1080p low preset at 60fps. In case you are looking to game at 1080p high preset at 60fps, the requirements go up to Intel Core i5-4690K or AMD's Ryzen 5 1500X, 8GB of RAM, and either an Nvidia GTX 970 or AMD R9 290X graphics card.
Unfortunately, the listed requirements do not include any higher resolutions but it appears that Anno 1800 will be quite hard on the hardware.
The game will officially launch on April 16th, and as noted, it will be available over at Ubisoft's Uplay and Epic's Games Store.