Crafting is an essential part of Path of Exile 2 - not only for gear.

Quick Reference

• Adding modifiers to items thus maybe increasing their rarity
• Consider using the best Item Bases for your build
• Reduce the amount of materials required by using Omens and Essences

The Fundamentals

Crafting is, generally speaking, taking different Orbs and smashing them on items to randomly add, change, or remove modifiers. This might also enhance the Rarity of the item. Starting from Normal, turning into a Magical item with one or two effects. Magical items can eventually be upgraded to a Rare item with up to 6 magical effects. Occasionally you can tarnsform a Normal item into a Unique item.

Here is a more detailed guide on the basics of crafting..

Item Classes

Every item in the game belongs to an Item Class. The most essential crafting materials is currency. All items that allow you to change the properties of an item can be found here. This includes all orbs, essences and destilled_emotions. We're going to talk more about them later on.
Besides those currencies you're going to need items to use them on. The two most common use cases will be Waystones and your equipment.

Item Bases

Items are further specialized by a Base Type. Where the Item Classe describes the general use of the items, the Base Type defines it's specifics. The Orb Of Transmutation for example is a currency which allows you to transform a normal item into a magic item and adding a modifier. This is true for every other item as well.

Omens

Omens come with a variety of mechanics including certain benefits for crafting. The Omen of Dextral Exaltation, Omen of Sinistral Exaltation and Omen Of Greater Exaltation changing the impact of Exalted Orbs.
Here is a list of the rest of them:

• Omen Of Whittling
• Omen Of Sinistral Erasure
• Omen Of Dextral Erasure
• Omen of Greater Annulment
• Omen of Sinistral Annulment
• Omen of Dextral Annulment
• Omen Of Sinistral Alchemy
• Omen Of Dextral Alchemy

Essences

Essences are like Orb Of Transmutations and Regal Orbs They add a modifier to a Normal or Magic item and upgrade them to Magic or Rare items respectively. The main difference is: The provided type of modifier is depending on the essence.