Gracious
Shavanna is a modern American elaboration of Siobhan or Shawna, ultimately derived from the Hebrew name Yochanan. It combines the phonetic elements of 'Sha' with the popular 'anna' suffix, following the pattern of names like Savanna.
Less common today
Shavanna isn't in the latest US Top 1000. It last peaked at #5,524 in 1990.
US births per 5-year period, 1990βpresent (SSA data).