Subscriptions for NoMachine software products activate the server component in the NoMachine software running on the machine you want to reach. This means that you need to install a subscription license on the remote "host" or "server" you wish to connect to. 

Once the appropriate NoMachine package is installed and activated on the target machine, you can connect to it to access a desktop or application running there. On the device(s) you are connecting from, you can install any NoMachine Player (aka Enterprise Client in earlier versions) if you prefer only a connection GUI. These devices are not counted, so you can install NoMachine client software on as many devices as you need.You can also install any other NoMachine package, given that they all ship the player component which is what you use to start connections. A software subscription is not required in order to install and use a NoMachine Player.

If the server-side software you install supports web-based connections you can connect from your device just using its web-browser.

You may also find the following articles helpful: