It's important to remember that "voilà" is an interjection, which means it's a word that expresses strong emotion or feeling and doesn't actually have a grammatical gender on its own. However, when used in a phrase, "voilà" can be treated as a masculine noun, meaning that you would use masculine articles or adjectives to describe it.
For example:
* "Voilà un beau cadeau." (Here is a beautiful gift.)
* "C'est un voilà vraiment intéressant." (That's a really interesting voila.)
* "Le voilà qui arrive." (Here he comes.)