First of all, you’ll need to clarify the question you’re asking.
You have asked
How would I center the text in the middle on here using only html?
but then you go on to say
HTML refers to the elements which give structure and semantic meaning to the page. e.g. <p>, <h1>, <a>, <img>, <div> etc.
Additional information which you can include within the tag are attributes. e.g. <img class="big-picture" source="images/mypicture" width="800" height="600"> The class, source, width and height are all attributes.
display:table-cell; vertical-align:middle is not HTML; it is styling information.
Are you asking how to vertically-centre the text using in-line styles? If so, then you will need to explain in what way the code @ronpat gave you in post #2 fails to meet your requirements, and what help you require in amending it.