The IP packet is a chunk of data that is sent over the internet. All data that travels across the internet is contained in packets that are reassembled by the device receiving the data.
IP packets consist of a header and a payload. The various bits contained communicate the type of packet (IPv4 or IPv6), the type of service, the length in bytes of the packet; the ID tag that helps put together various packets, and multiple other pieces of information. These packets are reassembled to display the combined contents on the receiving machine.