WhatsApp is now rolling out its new text formatting options including bold, italics, strikethrough and any combination of these. The basic text formatting was first tested in WhatsApp's beta channel in mid-March, but is now rolling out via official Play Store updates. From what we can see it should be working on any version from v2.12.535 and above.
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 channel WhatsApp update just added a quick reply function, multiple selection capabilities for chats and contacts and solid color wallpaper options.