Wrap the text in a single asterisk or a single underscore. As with bold, asterisks are the safer choice because they also work in the middle of a word.
All ways to write it
One asterisk on each side. Works inside a word too.Works everywhere*italic text*
One underscore. Not inside a word.Works everywhere_italic text_
Three asterisks for both.Works everywhere***bold italic***
Example
You type
The *quick* brown fox.
Set `retry` to _false_ only for ***idempotent*** jobs.You get
The quick brown fox.
Set retry to false only for idempotent jobs.
Questions
Why does my underscore italic show as plain text?
Underscores inside a word are not treated as emphasis, so file_name_here stays as typed. Use asterisks: file*name*here.
How do I write bold and italic together?
Use three asterisks: ***text***. You can also nest them: **bold with *italic* inside**.
Italic in Confluence
Markdown Macro+ renders *italic* and _italic_ as italic text. Markdown Importer converts it to Confluence italic formatting on import.