Hashtags are very useful. You can use hashtags that are relevant to the topic to draw attention to the post. Also, you may create your own hashtag as a brand name. Use different tools to find and manage your hashtags. Here are some general suggestions:
Facebook – Posts without hashtags outperform those with hashtags, however, you can add 1-2.
Twitter – 2-3 hashtags
Pinterest – 15-20 hashtags
Instagram– you can use up to 30 hashtags on a post.