A big question beginners will ask about playing Dungeons & Dragons, after 'why are you making me play this with you?' and 'how long will this take?' is 'what race should I be?'. At that point there's a conversation about how we don't say 'race' we say 'species' but that everyone's still getting adjusted to that, and eventually we face down the question - what species should you be? If you've come here looking for a definitive answer, I can't offer one, and that's because there isn't one. But it's still an interesting question to consider, no matter what your level of experience with the game is.
When it comes to building a character, there are two basic things to consider... both of which are incredibly complex, but let's not worry about that now. You can either create a character with the best story you can think of, or one who plays in the most effective and meta-powered way. It's possible to do both at once, but storytellers tend to roll with the Standard Array punches, and minmaxers tend to disregard narrative.
Species is a key part of this equation. If you're minmaxing, then you likely already know a lot of bonuses each species (and indeed class) gives you, and so you work cleverly within these bonuses to find the best path to success. If you're looking for storytelling, you might come up with something that ties to your species' backstory or lineage, or conforms or subverts expectations of this species. The point of all this is that there is no 'best species' (or 'best race') to play D&D as, because it depends entirely on why you're playing in the first place.
Some players may be in between this approach - they may play the game largely as themselves, rather than inhabiting the character. They don't consider their character's Intelligence when it comes to dungeon puzzles, they figure it out themselves or they don't. Their approach to each conversation is based on what they would do in that situation rather than the character as a separate entity. They're interested mostly in the wider story itself, and where that will take them, rather than their own arc. They don't necessarily choose their character with a narrative drive, but also aren't incessantly checking every bonus before making their choice.
The answer to 'what is the best race?' is another question - 'how do you want to play the game?'. If you're just looking to explore the gameplay without sinking in too deep, then Half-Elves and Humans are traditionally the easiest to just play along with, while Tielfings can be more complex and most beneficial for spellcasters, so usually harder for newcomers to get to grips with. Tieflings are at least in the Player's Handbook, however, and once you start exploring other playable races you can sink in deeper with a variety of bonuses to combine in all sorts of ways.
You might want to think about the theme of the adventure you're playing, the class you intend to pick, or the way you want to approach roleplay. Even if you aren't planning on fully immersing yourself in the character and making decisions as you would, you'll still need to consider the boosts you'll get for the typically roleplay-heavy skills like Deception, Perception, and Investigation. Do you want a character who fits into this world, or one who will stand out - and will your DM consider that as they shape the story? Do you want to play as a character well suited to their class, with all the associated bonuses giving them crucial boosts, or play against type to raise the challenge levels and experience something different?
Then there's how much of the 'classic D&D experience' you're looking for. Some of the lesser-used races are, well, lesser-used. It's not a typical D&D adventure to have a Water Genasi Fighter, a Harengon Warlock, and a Warforged Bard, but maybe that's what you're looking for. An Elf Paladin, Human Ranger, and Dwarf Barbarian is more typical, if you want the real deal.
There’s no wrong way to play Dungeons & Dragons, and as a result there's no perfect species to pick. As long as it's a race that you can tell a story about, works for your class, and gives you some boosts you can use, it's the perfect race for you. And even if it doesn't, you can probably make it work anyway.