For any given card, from either the reviewer:
Or the browser:
You can click on the ‘Suggest a change’ button and a window will open up in which you can suggest a change.
There are some guidelines for best-practice in terms of suggesting updates (if the update is content-related or factual it is asked that you include a source citation, etc.). A general guide to submitting suggestions can be found here: 📚 AnKing Step Deck Submission Guidelines
Once you make that suggestion it will go through to a moderation queue to be looked over by the deck maintainers for that deck. From there, it can be approved, rejected, debated, etc., which can take some time. Ultimately the final decision will be made by the team of maintainers/moderators and will take into account a lot of different factors that determine whether or not to push that suggested change out to however many tens of thousands of users there are.
Let me know if that helps, and if you have any other questions. 