I did some research on the proper use of the word “OK” because I always doubt whether I am writing it the correct way.
Is “okay” acceptable?
Does “OK” need periods (as in, O.K.)?
I found two helpful articles on the subject:
It turns out that all three are acceptable (OK, O.K., or okay), but OK (without periods and not spelled out phonetically) is the most common.
So, like a lot of common words in our English language, any of them work. Just be consistent.
Personally, I’m going to write OK from this point forward.
P.S. I did not know this, but no one knows for sure where the word OK even came from. It is not an abbreviation for any English word that we use now. Potentially, it came into usage as an abbreviation for “all correct” (“oll korrect”), but that is not for certain.