Jetpack doesn’t include any Biography box at the moment. If you’ve enabled the Google+ module, Jetpack will only add a badge at the bottom of your posts, like so:
http://i.wpne.ws/TNfs
You can activate this feature by following the instructions here:
http://jetpack.me/support/google-plus/#connect-profile
If you’d like add a larger Biography box, you should be able to find interesting plugins in the repository. Here are 2 examples:
http://wordpress.org/plugins/author-bio-box/
http://wordpress.org/plugins/post-author/
