Pattern Suggestion for this case?

Hi, Amazing site and guide!!! 

I am having a hard time figuring out what pattern would be best for the following case: 

I am building a javascript file (from TypeScript) for website owners that will improve the look of the their website by moving current elements to different placement on the page (i.e. move menu from the side of the page to the top), overwrite current design style with new styles to elements on the page, and if the customer wants, add new features like a chat box or site wide notifications.  This is a subscription service for business owners who use a certain type of website software and the script will check their license and load up a json config file before making changes on the page.  If they subscribe to extra features, the script would load up those extra features too.

Hopefully that makes sense.  Do you have any suggestions on what would be the best pattern to use?  I believe in the future I will add new features to load up and also may have to alter the code based on the theme the customer is using. 


PS, on a completely different side-note, I have been doing open-source intel with some private companies to help Ukraine out against Russia.  Keep up the good fight!!! There are many behind you.