The most common is to enter SQL Server through a network using the TCP / IP protocol.
SQL Express installs the disabled protocol by default, so you must enable it.
In Windows 10,
- go to the administrative tools of the control panel
- enters team management
- Services and applications
- SQL Server configuration manager
- SQL Server Network Configuration
- Protocols for the name of your instance
- look for TCP / IP in the right pane, enable it and go.
In addition, you can adjust in the properties by which of the network interfaces you will be listening and the port (by default the port is 1433).
In other versions of Windows, look for the SQL Server configuration manager in the start menu.