It is a unique set of numbers just like your mailing address where your online communications are sent to. It is your “online mailing address”. Most small businesses and homes have one router where several devices are connected to like your computer, laptop, phone, ipad, etc. Your online communications through these devices are sent to your router which sends and receives your information through your unique IP Address.
The role of your IP is to address, deliver and route your online request by attaching your IP address (Return Address) to it so that your can receive communications of your online activity. Unlike sending or receiving mail through a post office, all this happens within a fraction of a second.
Your IP address is assigned by the service provider you choose like, AT&T and Comcast. When you travel, your IP address does not travel with you. Your devices automatically routes your online activity through the IP Address of the public network that you connect your device to like at hotels, airports, cafes, etc.