You sure can. The basic plan gives you access to all features. Purchasing a premium plan remains optional, but it allows you to run unlimited sessions and download exclusive content from the discover section.
Find new subcategories in the Discover section. Then, use the search bar to find your favorite categories and decks.
You can create categories, subcategories, decks, and cards. You can also run sessions using your favorite decks.
Yes. This application works on devices running the iOS.
You can easily create an account using the Sign in with Apple.