One of the things you should know when working with PowerQuery is that you can get a list of all functions in M by adding a blank query and use the #shared expression to get all the functions.
This can be turned into a table by clicking the “Into Table” button on the ribbon and use the filter to find the function you want to learn about
Now when you click the cell “Value” for a given function the documentation of the function will appear below.
This is almost identical of what you can find online using the https://docs.microsoft.com/en-us/powerquery-m/power-query-m-function-reference – but you won’t have to leave the Query editor
But did you know
If you use the formula bar and
And complete it without parenthesis
You will get the documentation as well –
This is useful when you write your own Power Query formulas and need more info about the function that the intellisense gives you.