For very small projects, it may be possible to do deploy your code "by hand", that is, by manually typing the sequence of commands through the remote shell that are necessary to install a new version of code and execute it on a remote shell. Anyway, even for an average-sized project, this is error prone, tedious, and should be considered a waste of most the precious resource you have, your own time.
The solution for that is automation. The simple rule of thumb could be if you needed to perform the same task manually at least twice, you should automate it so you won't need to do it for the third time. There are various tools that allow you to automate different things: