Hello Krystyn,
It's been a number of years since I have used Articulate, having switched to Captivate a long time ago. But, for the most part, Articulate is already WCAG 2.1 AA compliant. By default, it is navigable by keyboard alone and has the ability to be captioned. The images should have alt text (with a good description) for all unless the image is decorative only.
Where you need to take note is for the interactions. If they cannot be done by keyboard, are tables (especially tables nested in tables) they require certain actions like row and column headers. The use of styles (think Word); Title, heading 1, heading 2, heading 3, Table, bullets are all required.
If you have documents inserted that the learner can access, make sure these are ADA compliant as well.
Make sure the written content is very different color than the background color. Notice the black text on white is easy to read, same with white on black. If you were to use Blue on Grey, it would be harder.
For quizzes, drag and drop are right out. That is hard for screen readers to handle.
I can actually go on and on. I used to teach a class on this. But, take a look here: https://www.w3.org/WAI/WCAG22/quickref/. It is a quick reference guide on this. Also, test it. NVDA is a good screen reader to use to test your course; https://www.nvaccess.org/. If you host the product, use an accessibility checker to get some feedback. Here is Articulates report on accessibility as well: https://www.articulate.com/about/accessibility/storyline-360-accessibility-conformance-report-vpat/.
I hope this helps.
Scott Burnett