You’ll definitely want to study DevOps and SysAdmin if you’re looking for general knowledge. O’Reilly textbooks are a good place to start. If you’re website is entirely static, you can actually host it for free with Github Pages. For deploying a .NET (or really any) app you probably want to look into how to package it into a Dockerfile. That makes it platform agnostic and bundles every dependency into an easy to deploy image. After that you probably want to look into setting up Heroku to put your app on the internet. You’ll also want to maybe register a domain and configure DNS if you want a proper domain name, but that’s comparatively simple.

If you’re going the AWS route, you’ll want App Runner or EC2 for the app itsel), RDS for database, and maybe even API Gateway to sit in front of your service and route request/terminate authentication. You could even configure everything with code using an Infrastructure-as-Code tool like Terraform.

If you can’t tell from the number of links, the barrier of entry to AWS is much higher but it’s worth getting your head around depending on where you want to go. Maybe leave it until you’re a bit more comfortable with building an deploying apps though, I’m mainly mentioning AWS to give you an idea of what you might want to head towards, you should probably stick with Heroku for now.