Some Windows 10 devices have a SIM card and/or eSIM in them that lets you connect to a cellular data network (aka: LTE or Broadband), so you can get online in more places by using a cellular signal.
If your Windows 10 device doesn’t have a SIM card or eSIM, you can still connect to a cellular network by plugging in an external cellular device (also called a cellular modem or mobile broadband device). However, these external cellular devices will often have their own settings instead of being able to use the built-in Settings > Network & Internet > Cellular settings in Windows 10.
You can use a PIN for the SIM in your Windows 10 device to help prevent other people from using the cellular data connection when they are not authorized. After you have set up your SIM PIN, you will be prompted to type the SIM PIN when you try to connect.
This tutorial will show you how to set up and use a SIM PIN for a cellular data connection in Windows 10.