I see two questions
What toolboxes are required for the function I want to send?
You need to generate a Dependency Report. As you can see in the link I've posted, the required toolboxes are listed towards the end.
Another way to get that information is depfun - this will give you the files your function depends on.
THIS is probably what you really want - depdir - it will list the dependent directories of your M-file.
What toolbox does my function belong to?
You can get that information with the which command - it will tell you where it's located and indicate if it's a built-in function.