I can’t figure out why my author bio is empty (at the end of posts/pages)

Hi. I have tried everything. I added picture to Gravatar, I written my bio at both Gravatar and wordpess users profile, however the box below each post is empty (doesn't display anything). Do I have to turn it "on" somwhere so that it start displaying or how do I display author bio at the end of my posts / pages?