Terraria doesn't have a leveling up or player class system in the normal sense. However, it does have distinct sets of weapons and armor that can benefit a specific playstyle.

There are 4 types of damage in Terraria*, being: Melee, Mage, Ranger and Summoner. Each have their distinct pros and cons. And unique armor sets that can boost their damage.

*Some items, like Bombs, do classless damage, which means the damage they do will not be affected by any kind of boost that would normally affect these types of damage, I'm gonna call them classes for the rest of the guide. also you can theoretically mix armors to gain better stats for all weapons but thats elite ball knowledge and you shouldnt really worry with such a headache if you just began playing

Melee, as the name implies, is damage inflicted by close combat weapons/low range weapons (think swords, spears, yoyos and the sort.), however as the game progresses you get melee weapons with larger range, which makes melee very viable for bosses later on.

the armor sets that benefit melee armors tend to have the highest defense from any armor sets, so it's definitely a viable choice for new players since you aren't at the risk of dying to literally everything.

PROS: good defense, good damage, and you can obtain melee weapons earlier than any other class.

CONS: for half of the game you have the lowest range of every class so you really have to get close to enemies and bosses, normally this would be fine but terraria is mostly balanced around keeping your distance from the enemy so you can see the problem, and also it has the worst multitarget damage from any class so in invasions you're gonna struggle compared to every other class.

Ranged, on the other hand, is a jack of all trades, it's almost like a medium term of every other class. It uses guns and bows, has good armor and damage at every stage of the game. and it can afford to be pretty far away and still do very good damage.

PROS: good defense, good damage, and range!

CONS: Ranged weapons do depend on ammo and arrows for the most part, except some rare exceptions. you're prone to missing fast targets since you have to aim, and while there is a type of bullet that can auto-aim enemies later on in the game, it comes at the cost of damage. Oh, and also the pros of every other class can outclass ranger.

Mage is part of the shadow wizard money gang, and it loves casting spells. Ok just kidding but mage has the strongest single-target damage out of any class at the exchange of defense, it uses spelltomes and staffs (and other flashier stuff later in the game), and it has decent range, not as much range as the ranged class but just enough to stay out of danger.

PROS: VERY good damage, has the coolest weapons in the game and has medium tier range.

CONS: bad defense, and all your weaponry is limited by your mana.

Summoner is objectively the toughest class for new players, so i wouldn't recommend it to them but in exchange it gets the best crowd control and multitarget damage out of ANY class, perfect for invasions and bosses who spawn enemies. It uses whips and minions together to shred through enemies, but it has the worst defense at every stage of the game.

PROS: INSANELY good mutlitarget damage, and VERY good single-target damage, with a summoner focused setup you'll have the highest DPS (damage per second) out of any other class in the game.

CONS: HORRIBLE defense, the worst, in fact. And you don't have the best range, so you have to stay close to deal the best damage. And also armor sets and potions that benefit summoner and its weapons are Very grindy most of the time, its the high risk high reward class, basically.

TL;DR: theres different types of damage in terraria and they can be boosted according to your gear. if you're a new player id suggest somewhere along the lines of melee and ranger, but if you're more experienced id suggest mage and summoner, but if you wanna take it up a notch you can combine different armor pieces and accessories to boost different types of class damage.