My search terms seem like they would apply to one of my articles, but the intended article does not appear when I search. Why does that happen?
As described in this article, the Help Center end-user search (which is relied upon for both traditional search and suggested articles when an end-user types a subject on a ticket form), takes certain factors into consideration including an article's title, labels, and body content. Taking this into consideration, there are a couple of other factors which may impact your articles:
Your query is not spelled correctly. Search does not assume what a searched word should be. So if the word is misspelled, you may not see any results.
Additionally, the search is looking for a 2/3 match of search terms to the article content. If an end-user uses an entire sentence as a search query, but over 1/3 of those terms do not appear in your article(s), there may be a lack of articles returned by a particular search.
In both of these cases, you could consider modifying the article title or content, or adding labels to the article. Labels would be less apparent to the end-user, but if people are consistently misspelling a word, it may be helpful to add that misspelling to an article as a label to help them find the intended content. Making the article a better match for common end-user searches will allow your users to better serve themselves.