Much like other apps that support formatting text, you simply add a symbol to either side of the word or phrase you wish to format.
To bold something, add an asterisk to either side of the word: *bold*
To italicise something, add an underscore to either side of the word: _italics_
To strikethrough something, add a tilde to either side of the word: ~strikethrough~
You can combine any of these options together simply by adding the relevant symbols to either side of the word or phrase
When you receive messages from someone with the latest version, their name will be bolded in the notifications shade and the formatting of the message will also show up. For those that are wondering, the latest beta channelWhatsApp update just added a quick reply function, multiple selection capabilities for chats and contacts and solid color wallpaper options.