In computer networks, to upload can refer to the sending of data from a local system to a remote system such as a server or another client with the intent that the remote system should store a copy of the data being transferred, or the initiation of such a process.
It helps to transmit the data from a computer to a bulletin board service, mainframe or network. For example, if you use a personal computer to log on to a network and you want to send files across the network, you must upload the files from your PC to the network.