Hey guys!

I have been looking into ways that we can transfer data over from our pc game to a mobile app in a cloud-based fashion. We were planning to have users sign into our own web api through Steam on the PC game and on the Mobile game. This would allow us to store game information based on the user's steamid that can be passed between the mobile game and the pc game. What ways is this sort of cloud based implementation done? What do people usually use to accomplish something like this?

If you use an existing API (Google Play services, Apple Game Center, Facebook Game Room, Steam, or others) then you use the SDK that comes with that API. The SDK will also come with a bunch of examples and documentation of how you can use it.

If  you end up building your own, then you'll typically build a web service layer that can receive requests from games, log in players (using cookies or session tokens) and store/retrieve data. Probably also do sanity check on the data, to try to catch some cheaters.

The specifics depend on the particular platform you end up choosing. Without knowing what you want to accomplish in more detail, and what specific SDK you're using, it's hard to give any more specific advice. Get the SDK, try the samples, read the documentation, and then ask more if there's somthing in particular you don't understand!