In most cases it will be an Ethernet cable with an RJ45 head, both Cat5 and Cat6 Ethernet cables will do.
Go into a good electronics store and ask for an Ethernet cable of your desired length, they'll normally be able to make one for you.
Either use a crossover cable or connect them using a hub, switch, or router.
allows a single computer to connect to a LAN allows a single computer to connect to a LAN
In ethernet terms, a straight-through cable connects a client device to a hub, switch or router (straight-through meaning the connection is pin-to-pin, the opposite of a cross-over cable, which connects RX-TX and vice-versa).
a hub
With a LAN cable and a switch
For a small LAN network, a switch is best. To connect two or more LAN networks, a router is required. (2) From Jean Andrews CompTIA A+ sixth edition (page #852): You can use a crossover cable to connect to computers without a switch or hub making it the simplest network of all. For two or more you will need a switch, hub, or router.
A server is not necessary to create a LAN. You can connect all of the devices using UTP cable and a switch or router (a hub would work too, but they are slower devices).
RJ45
Crossover
You do not have to connect your router to your PC via ethernet cable, you can instead connect via wi-fi and your router must be connected to your hub.
It is when you connect 2 computers with a LAN cable
Crossover Cable (T568A on one end, T568B on the other)