Cant post in Announcements. Its tricky to get any text modification etc so here's a few options.

If you want

Itallics text put 1 * either side of the text you want changed like so:- *Italics*
Bold text put 2 ** either side of the text you want changed like so:- **Bold**
Bold and Italics use 2 * and 1 _ either side of the text you want changed like so:- **_Bold Italics_**
Strike Through uses 2 ~ either side of the text you want changed like so:- ~~Strikethrough~~
Underline put 2 _ either side of the text you want changed like so:- ___Underlines___

Also
Blockquotes require 3 ` either side of the text you want changed like so:- ```Blockquote```
Inline Quotes (I think) require 1 ` either side of the text you want changed like so:- `InLine`

Not sure what other options are there, but you can search Mark Down text and play around with it.