Here's the syntax in Markdown for strong and em text:
**Here's some strong text**
*And here's some emphasized text*
__Alternate syntax for strong text__
_Alternate syntax for emphasized text_
Result
The above results in the following HTML:
<strong>Here’s some strong text</strong>
<em>And here’s some emphasized text</em>
<strong>Alternate syntax for strong text</strong>
<em>Alternate syntax for emphasized text</em>