This is a somewhat comprehensive guide on What markdown SP allows and how to do it - this is not an offically endorsed guide.
This may not be fully complete or up to date with current SP versions, at the time of making this, SP's version is 1.9.0 - 258.
**bold**
__bold__
*italics*
_italics_
**_bold italics_**
__*bold italics*__
___bold italtics___
***bold italics***
~~strike through~~
# heading 1
## heading 2
### heading 3
#### heading 4
##### heading 5
***
---
___
> this will create a block quote
>> this will create a block quote within the first.
+ list
- also list
* is as well
– creates list indentation
— big indentation line
1. this will make a list
2. big lists
1. but you can also keep the number as 1
1. it'll automatically count them in number order when you're out of editing mode
`backticks create code blocks`
``as far as i'm aware``
```there's no difference in how each of these function or show up on SP```
[but text in these brackets](with the link here, will hide the link behind the text to make clickable text)
![with the exclamation mark, the text you put here could be an image description](with a direct link to the image here)