The reason you would need multiple NIC in your computer is when you want to create configurations in which an instance connects directly to several VPC networks.
Each of the interfaces must have an internal IP address, and each interface can also have an external IP address.
A PC or computer can have more than one NIC.
For example if you want to assign a few different IP addresses to one computer then you can do so with one or 2 NIC devices.
Or a WiFi NIC can be installed as well as an Ethernet NIC.
A PC or computer NIC is a Network Interface controller or Network Interface Card.
A network interface controller is a computer hardware component that connects a computer to a computer network.
Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus.
The network interface card (NIC) or network card is the hardware device most essential to establishing communication between computers.
Network Interface Card is a hardware device that is installed on the computer so that it can be connected to the internet.
Every computer must have at least one NIC if it wants to connect to the internet.
NIC is not the only component that is required to connect to the internet.
Notebooks are normally build for consumers, most of these consumers do not have any need to use multiple NICs.
Most notebooks can therefore connected to one LAN and/or one WLAN.
In a desktop computer, the network card is most often located near the USB ports on the back if it's an onboard version.
If it's a separate network card expansion card (not onboard), it usually is on the back of the computer, near the bottom, taking up a PCI slot.