When one wants to write a piece in which a 1 syllable word is split between multiple notes, how is this shown? Or a multiple syllable word over the same number of notes? A visual representation/example would be helpful.
When you have one syllable to two or more notes, simply slur those notes together. When you have two or more syllables to the same number of notes, put a dash (-) between the syllables and be sure to place each syllable directly below its note. No need for a visual representation because it's easy to follow.
Music that contains single syllables or short words sung over several notes is called melismatic. There are many examples in the musical literature. Your question seems to indicate that you have not spent much time looking at vocal/choral scores. I recommend you do so since you are writing a choral piece. I imagine you have other questions as well which will be helped by perusing a bunch of scores.