You can use a subset of standard Markdown syntax for formatting your message.

Headers

 
# H1
## H2
### H3
#### H4
##### H5
###### H6
Alternative style with udnerline:
H2
---
        

Emphasis

 
*italics* or _italics_
**bold** or __bold__
**_combined_**
        

Lists

 
1. First ordered list item
2. Another item
   * Unordered sub-list.
1. Actual numbers don't matter, just that it's a number
   1. Ordered sub-list
4. And another item.
   Indent with spaces in the same paragraph.
* Unordered list can use asterisks
- Or minuses
+ Or pluses
        

Links

 
[inline link](https://www.google.com)
[inline link with title](https://www.google.com "Google's Homepage")
        

Images

 
![alt text](https://url.com/img.png "Title Text")
        

Code

 
Inline `code` has `back-ticks around` it.
Block of code:
```
let awesome = 42
```
```fsharp
printf "With syntax highlighting"
```
or indented by 4 spaces:
    let text =
        "Hello world"    
        

Tables

 
| Tables        | Are           | Cool  |
| ------------- |:-------------:| -----:|
| col 3 is      | right-aligned | $1600 |
| col 2 is      | centered      |   $12 |
| zebra stripes | are neat      |    $1 |
        

Blockquotes

 
> Blockquotes are very handy.
> This won't break line.
        

Horizontal Rule

 
Three or more...
---
Hyphens
***
Asterisks
___
Underscores
        

Line Breaks

One new line will not start a new paragraph or break the line. For that use two or more newlines.

Source and more detailed information.