A hashtag is a search term. It’s a word or a phrase with the # before it. Adding that sign makes the term searchable on Instagram. Hashtags are amazingly helpful for brands.
If you consider what your ideal client might be searching for and you add that hashtag to your post, your avatar will have a much better chance of finding you.
But don’t think that just because you post a hashtag your post will be found. If only it were that easy!