🔼The name Gabriela in the Bible
The wonderfully pretty name Gabriela does not occur in the Bible (so it's technically not a "Biblical female character"). It's the Hebrew name Gabriel made feminine in a Latin way, and that makes it very un-Hebrew indeed. Gabriela is not a Hebrew name. But, if we would want to transliterate the Latin name Gabriela back to Hebrew, all we have to do is add the letter he to create the ah-part.
The ah-part comes from the regular feminine extension, which would turn a regular masculine noun into a feminine one. But a Hebrew name doesn't really need that because there are plenty men in the Bible who have feminine nouns for names (Ezrah), and also a woman or two who have masculine nouns for names (Tamar).
The name Gabriel translates into something like God's Guy, so making that feminine takes a trick or two.
🔼Etymology of the name Gabriela
The first part of our name Gabriela comes from the verb גבר (gabar), meaning to be mighty:
Obviously, if we would want to create a feminine version of Gabriel that is actually Hebrew, we would end up with something like Geburaiel or Gebirael. The name Gabriela can't be translated, but still, it could probably be interpreted to mean Mighty Woman Of God.