Just go to your favourite search engine, I recommend, StartPage.com or DuckDuckGo.com, and search on the following terms.
Steemit witness
Steemit witness voting
Since you appear to be interested in how things work on Steemit, I highly recommend you follow the account of @paulag as she does statistical analysis of the Steemit data so that you are properly informed about what is really happening on Steemit, rather than listening to the gossip and rumour.
Many thanks @leoplaw for the suggestions and info.
I really appreciate it :D