When working with Power Query, you have probably already realized that every expression you write returns a value of a specific type. Usually this will be a primitive type like text, number, or date. (A full list of types available in Power Query can be found here: https://docs.microsoft.com/en-us/powerquery-m/m-spec-types). If for some reason the type of an expression cannot be defined, the special type *any* will be used. For sure you already encountered this when using Table.AddColumn which, by default, results in the new column being of type *any*.
Read on to learn more, including what you can do if you’re creating Power Query functions.