I have a category in the income field that should be an expense. How can I transpose it? (Q Mac)

Open up the Categories window from the Window menu. You can make changes to your categories from there, just double click on the one you want to change.

If the category you wish to change to an expense is a subcategory you'll need to drag it out of its parent category to make it a top level category & then you can change it. Also, there are certain categories that Quicken requires & you won't be able to change those.