Whenever I conduct a grammar workshop, a participant will invariably ask, “How many spaces should you leave after a period?” The answer is one — for a computer. (You use two spaces after a period when working on a typewriter.)
It is amazing how concerned some people are about this issue. Frankly, I don’t seriously believe a reader will be distracted from your work whether you leave one or two spaces — just be consistent. However, some people do tend to focus on this item. That’s probably why you have a feature on your software program to assist you.
Click on Tools / Options / Spelling and Grammar / Writing Style: (set for Grammar and Style) / Settings / spaces required between sentences.
You then have three options: check for one or two spaces or don’t check. I would recommend setting the feature to either the one or two spaces. That way, at least, your material will always be consistent.
Here’s something interesting though. People often wonder why grammar changes. One of the reasons is technology.
We were taught to always put a punctuation mark at the end of every sentence. But what happens if the sentence ends in a website or an email address. If I add a period, I may confuse my readers about the address. Therefore, in these specific instances (websites and email addresses) I would not put anything at the end of the sentence. Hopefully, I am at the end of a paragraph.