There's now the apa6 package on CTAN. I can't think of much in the way of changes from 5th to 6th that needs support in the apa class, but you will need to make changes to how you handle bibliographies. It is wise to use this class file when submitting to the editors for refereeing. A new puthesis.
Purdue has an Overleaf license so you can use LaTeX on the web. We strongly recommend candidates consider learning puthesis prior to the writing process. American Psychologgical Association, , p. As far as puthesis is concerned, these commands can be used anywhere.