World anvil is a website that people can use for world building, the practice of creating a fictional setting and inventing details about it. World anvil allows authors to organise their setting and share it with an audience in a way that is meant to be simple and convenient.
It has categories to organise all your information, materials, countries, family trees, maps and much more. This is in theory an efficient way to keep track of all your world building work, In theory.
I personally find World anvil difficult to navigate as each category is split into increasingly more specific sub-categories. On top of this unless you pay, your work is publicly available.
Overall it is a useful software but it is slightly too complex, in my opinion.