Install the free NoMachine package or any Enterprise server product on your computer and do the following:

1. Open NoMachine (!M icon in system tray or from your computer's applications menu)
2. Go to Settings -> Network -> Machine
3. In the 'Network machine' panel click on the 'Add' button

Clicking 'Add' automatically connects the computer to NoMachine Network and generates a unique Machine Id which identifies it.

You can now use the Machine Id to access that computer over the Internet. Go to another device, open the NoMachine Player and insert the Machine Id when you create the connection.

https://www.nomachine.com/support/documents/getting-started-with-nomachine-network 

If you wish to remove the machine from NoMachine Network, click on the 'Disconnect' button in the Machine panel to disable access. This will prevent the computer from being accessed over the Network service. The computer will still be available using its IP address (make sure that 'Let this server work only as NoMachine Network host' is disabled).

You can also assign a new Machine Id to your computer by clicking 'Generate new Machine Id'. The same for the Access Id, which is a further level of security: click on the link 'Generate new Access Id' to create a new id or on the link 'Don't use an Access id' to disable it.

If you want to allow access only through the Network service, enable 'Let this server work only as NoMachine Network host' in Server settings > Ports > Server ports. Enabling this option disables access using its IP address.