Voilà is a very common word in French, and depending on the context, it can take a number of different meanings, the most general of which is "there/here it is." In grammatical terms, voilà is categorized as a presentative, or a word that is used to introduce something. Voilà comes from the imperative phrase vois là (see there), which makes the presentative nature of the word even more apparent. At its most basic, voilà is used to present a specific object or person
Donc voilà mon super falafel, avec de l'aubergine grillée...
So here is my super falafel, with grilled eggplant...
Caption 9, Mon Lieu Préféré - Rue des RosiersPlay Caption
Ah! Ben tiens, voilà Socrate.
Oh! Well look, here comes Socrates.
Caption 9, Il était une fois: l’Homme - 6. Le siècle de PériclèsPlay Caption
In these two examples, we see how voilà can be used to direct our attention to both an object (Caroline's "super falafel") and a person (Socrates). But when voilà isn't literally presenting us with something, it is often used as a way of emphasizing a statement:
La poésie c'est comme l'amour:
Poetry is like love:
c'est le plus court chemin entre deux êtres. Voilà.
it's the shortest path between two people. There.
Caption 39, Marché de la Poésie - Des poètes en tout genrePlay Caption
In a sense, you could say that voilà is "presenting" us here with the metaphor on poetry that precedes it. But on a slightly less articulate note, when voilà is used for emphasis, it often acts as a sort of filler word, used when someone wants to end one topic and move on to another:
Euh... voilà. Après, l'inspiration, elle...
Uh... there you are. Well, inspiration, it...
elle vient de plein de sources diverses et variées.
it comes from a lot of different and varied sources.
Caption 48, Niko de La Faye - "Visages"Play Caption
You can also use voilà to affirm another person's statement:
Voilà, vous pouvez même voir le petit bateau en photo, euh, ici.
That's right, you can even see the little boat in the photo, uh, here.
Caption 50, Arles - Le marché d'ArlesPlay Caption
Or you can use it to express a period of time:
Voilà près de sept ans que les professionnels du bois attendaient ça.
For nearly seven years, the lumber business has been waiting for this.
Caption 5, Le Journal - FirewoodPlay Caption
Because voilà can be used in so many different situations, it is often tricky to translate ("there," "here," "there you go," "there you have it," "that's it," "there you are," and so on). And since no English word can really capture voilà's breadth of meaning, sometimes it's best not to translate it at all. In fact, the difficulty of translating voilà might be why it's become an (often humorous) English exclamation as well.
Now let's take a look at voilà's sister word, voici (from vois ici, "see here"). Like voilà, voici is also a presentative, but whereas voilà can either mean "there it is" or "here it is," voici usually just means "here it is." And unlike voilà, voici isn't used for emphatic or filler purposes, but almost exclusively for introducing or presenting a specific person or thing:
Nous voici devant une des quatre Statues de la Liberté
Here we are in front of one of the four Statues of Liberty
que l'on peut trouver dans la ville de Paris.
that you can find in the city of Paris.
Captions 24-25, Voyage dans Paris - Jardin du LuxembourgPlay Caption
You can get a better sense of the difference between voici and voilà when they are both used in the same sentence:
Voici ma maison et voilà celle de mon ami.
Here is my house and there is my friend's.
As you can see, voilà is used to point out something at a distance, whereas voici indicates something close by. The difference between voici and voilà is similar to the difference between ceci (this) and cela (that). In fact, another way of translating the sentence above would be, "this is my house and that is my friend's."
You've probably heard voilà used in English before, but voici hasn't really managed to make the crossover. Besides the fact that voilà is often hard to translate (voici is much more straightforward), this could also be because voilà often acts as a standalone phrase (Voilà!), whereas voici generally doesn't. But don't underestimate a good voici when speaking French: if you want people to notice something that's right in front of them, it's the word to use!