In Path of Exile 2, you will be able to Salvage items with Quality at the Salvage Bench (unlocked in Act 1 side quest) to gain special Currency Orbs that improve the Quality of different items. Salvaging items permanently destroys them, so make sure you’re only using this on items you don’t want to keep!
Unless improved through special mechanics, items have a maximum quality of 20%.
Lastly, while the first three Quality items are common, you can farm for more of them by picking up and salvaging Superior items, so don't stress too much about using them. Keep in mind you'll need about 15 to quality an item to 20%. (Except for GCP which will require less)
Blacksmith’s Whetstone
Martial Weapons gain 1% More Physical Damage per Quality.
Rarity: Common
Salvaging Superior Martial-Weapons with Quality will grant Blacksmith’s Whetstones that will increase the Quality of that item by 1 or 2%. “Martial Weapon” refers to Weapons that are used to make attacks, like Bows and Maces, rather than Wands which are the preferred weapons of spellcaster builds.
Arcanist’s Etcher
Effect of Quality Varies
Rarity: Common
Salvaging Superior Caster Weapons grants Arcanist's Etchers. The Quality effects vary on different Caster Weapons. On Sceptres, increasing the Quality will increase the amount of Spirit it grants, whereas Quality on Wands and Staves improve the quality of the Skill granted by that item.
Armourer’s Scrap
Armours gain 1% more Defences per Quality
Rarity: Common
Salvaging Superior Boots, Gloves, Body Armour and Helmets with Quality will grant Armourer’s Scraps that will increase the Quality of similar pieces of gear.
Gemcutter’s Prism
Effect of Quality Varies per Skill Gem
Rarity: Rare/Uncommon
Gemcutter’s Prisms, also known as GCPs, can be used to increase the Quality of a Skill Gem by 5% per use, up to a maximum of 20%. The effect this has on a Skill Gem varies, but you can see what Quality on each Gem does by hovering over it and pressing Alt.
Glassblower’s Bauble
Flasks gain 1% more Life and Mana Recovery per Quality
Rarity: Rare/Very Rare