question

Yes, any server executable that is compatible with Windows Server 2K12 R2 will run in our server hosting. Here's the complete tutorial detailing how to use hosted servers in our service: https://api.playfab.com/docs/tutorials/landing-tournaments/custom-game-servers

For a matchmaker specifically, your requirements will determine which type you'll want to use and how best to manage it in our hosting. For example, your model may be that you have a "lobby" server where players can do little more than chat and specify the game type they're looking for. You could easily host thousands of players at a time on a server like that, and it would use our Matchmaker API (https://api.playfab.com/documentation/matchmaker) to start up game sessions and assign players to them.