Almost all computer keyboards have a key marked Return or Enter; the two names are synonymous. The Return key moves the cursor (or insertion point) to the beginning of the next line. But more important, it returns control to whatever program is currently running. After a program requests information from you (by displaying a prompt), it will usually not respond to your input until you have pressed the Return key. This allows you to correct typing mistakes or to reconsider your entry before it is too late. In many applications, pressing the Return key moves the cursor to the next field.
In technical documentation, the Return key is sometimes signified by an arrow that looks something like <-'.