Gracious
Evanne is a feminine form of Evan, which is the Welsh variation of John. It shares the same etymological roots meaning 'God is gracious' and is often used as a rare, more melodic alternative to the more common Evan or Yvonne.
Less common today
Evanne isn't in the latest US Top 1000. It last peaked at #6,952 in 1990.
US births per 5-year period, 1990βpresent (SSA data).