What Languages Do I Need to Learn for My Desktop App

So I’m a little daunted and stuck, and wondering where to turn… I have intermediate knowledge of HTML/CSS but taking refreshers via Codecademy. However, I’m here on Codecademy specifically to help my skills because I’m looking to develop a HIPAA compliant desktop application for our healthcare clients. I run a successful business of building websites and performing marketing for clients, but we’re looking to move into the development field as well.

Codecademy does a decent job of explaining course curriculum if you have a goal of obtaining a career in “XYZ,” but not for specific application types as I mentioned above. So I’m hoping someone can point me in the right direction so that I can start taking the needed classes to learn more (even if it’s learning enough to make the right hires afterwards).

We’re looking to build a desktop application that is basically a dashboard with separate client logins. HIPAA compliance will be a second issue I’ll need to tackle as well. But for the dashboard we’d like to have the ability to create embeddable web forms and have those form submissions filter into a “client” profile (i.e. HIPAA compliant forms). The dashboard would also have built in functionality for sending/receiving secure emails and possibly a calendar. Our roadmap for future additions to the dashboard would be API calls for Google Analytics (data sorting & visualization) as well as some email/SMS texting for business review solicitation.

I’m assuming the basic code knowledge/libraries would be HTML, CSS, Javascript. I think learning more sophisticated libraries like React might be the best for this application. Not sure what else I’m missing?

Any help would be super appreciated! Thank you in advance and looking forward to using Codecademy to learn all that I can!