Eventually, any writer who is serious about the craft will start to think about sending work to a publisher or agent for consideration. If the creator has ever attended a publication workshop or Googled for instructions, they will take great pains to “get it right” according to whatever method they've come across.
But just what does “getting it right” entail? There is a standard formatting system that is preferred by many publishers, particularly those in the short story market and more especially the American speculative fiction short story market. It involves using Courier or Courier New fonts, double spacing the lines, indenting five spaces at the beginning of lines (opinions vary as to whether or not the first line after a line break should be indented) using a hash as marker for line breaks and not using widow/orphan control. A useful version of this, written by Vonda McIntyre, can be found at http://www.sfwa.org/2008/11/manuscript-preparation/.
Yet there are many publishers who dislike Courier fonts and specifically request, for example, Times New Roman. Some say one and half spaces between lines are fine. Some want the synopsis double-spaced; some say this applies only to the manuscript. Some don’t say what they want at all.
I suspect these things are not as cut and dried or even quite as important as some pundits would have us believe. I've seen several mss by published authors that varied widely from the commonly accepted standard. For example, one uses a pair of tildes, centred, as her line break markers; one uses three asterisks, centred, and another uses a hash but prefers not to centre it. I've seen at least one ms by a published author that just left the gap with no marker at all. And I have edited material by published authors that was not even double-spaced! Mind you, these people are all fine writers, far better than I, and they could probably write the ms by hand on coloured paper and get away with it. As a new author, I would not dare do that, and neither, probably, should you!
While we need to give ourselves every chance in this wretched publication gamble, the important thing is that we have good stories, set out in a way that's easy to read. All the hopeful new author can do is read the guidelines on the publisher’s or agent’s website and stick to them to the letter, and if no guidelines are given, just use something like the above method and cross your fingers. As with all things, there's no profit in sweating the small stuff. After all, in a hundred years - or even five years - it will not matter at all!