You can use different ways to enter pitch [0].
A common way is to use the "octave.pitch" format, such as 08.04, where 08 is the central octave (if I remember correctly) and 04 is the note E. It's common to use a score generator such as PythonScore [1, 2], and some people (myself included) like to use a regular programming language to generate the scores. I've used Common Lisp, Tcl, and Python in the past. Csound has a few frontends [3] that people may like.
AFAIK, Csound can read notes from a MIDI keyboard as well.