Here is a big title.
The text has a line of hyphens under it. (in the editor obviously xD)
Here is a bigger title.
The text has a line of equals signs under it.
How this looks in the editor:
Here is a big title
--------------
Here is a bigger title
==============
You can also use #. ## for the smaller title, # for the bigger one.
commented 5 hours ago by Sempiternus
Or you can use html, with the < h1 > - < h4 >tags. commented 2 hours ago
by Sir Terlor
(no space inbetween the < > and the number)