From the New User FAQ regarding cancelling your subscription:
When you cancel your subscription, you won’t receive access to future releases of Unreal Engine 4, however your login will remain active, and you are free to continue using the versions of Unreal Engine 4 which you obtained as a subscriber under the terms of the EULA.
Your subscription also enables deployment, so that is gone when you cancel as well. From the FAQ again:
Unreal Engine 4 subscription enables you to deploy to Windows PC, Mac, iOS and Android. This is all available through the engine and tools download from this website.
Deploying an HTML5 game is currently experimental so it’s not available in the Launcher version of UE4. You’ll have to compile source from Github, which requires an active subscription. Read this documentation to get started: