Headings come in many different sizes. While in HTML an h1 heading is denoted by <h1>, in wikitext, it is denoted by an = sign. For instance if I wanted an h1 heading I would type what is below. However, it is unadvisable to use h1 headings in an article, always use h2 headings such as the ones below.
= h1 =
h1
edit== h2 ==
h2
edit=== h3 ===
h3
edit==== h4 ====
h4
edit===== h5 =====
h5
edit====== h6 ======