Writing in voice is capturing the real you on paper. Not everyone ennunciates words the same, many drop the ‘ing’ so ‘going’ becomes ‘goin’ and etc. When you capture your voice in your writing it simply means how you will sound on paper. The best way to find your voice in writing is by writing dialogue. Just pretend to have a conversation with someone you know and write about an event or something special in your life. Then take the same topic and write it as if you were talking to a complete stranger. There should be a difference in the the voice or words used in each exercise.