Keyword in the H1, H2, H3 Tags
These tags, which you can easily set in WordPress by highlighting the word and then dropping down to the Htag you prefer change the font size. They also indicate to google that they are an important part of the document.Htags often also function in things such as a table of contents, which by default plugin settings may create a toc based on the htags.
Although the weight of the Htags in the Google Algorithm is debatable, it is still a best practice to use them.
The policy is to only use one H1 tag and that should be saved for the main keyword on the page. It is the most important followed in order by h2-h6.
H2 and H3 tag make for good paragraph headings and as a best practice could include keywords related to the main keyword on the page.
To create an Htag simply access your code view and add <h1> to each side of your keyword for a heading one tag or <h2> for heading two and so on. Example: <h3> This is your keyword<h3>