You can attach Materia to your gear to increase its stats. Different types of Materia boost different attributes.
You can create Materia by extracting it from gear that has 100% spiritbond. This doesn't destroy the equipment, just reduces the spiritbond to 1%. Your gear's spiritbond increases as you earn EXP.
Creating Materia
To unlock Materia Creation, complete the quest
Forging the Spirit in Central
Thanalan. This quest is available from Swynbroes if you have completed the
level 19 Main Scenario Quest Life,
Materia and Everything.
When you earn EXP or perform actions that would earn EXP, your gear also earns experience in the form of Spiritbond. When Spiritbond reaches 100%, you can convert the gear's Spiritbond into Materia, which resets the Spiritbond of that piece of gear to 1%.
To extract Materia from spiritbonded gear, you can right-click the gear and choose Extract Materia, or if you go to Main Character > Actions & Traits > General, you will find Materia Extraction, which you can drag to a hotbar or assign to a crossbar. The Materia Extraction window allows you to view the Spiritbond of the gear you have equipped as well as any gear in your Armory Chest and inventory.
Gear with 100% spiritbond is shown as a white dot in the Inventory Grid.
Melding Materia
After you complete the Forging the Spirit
quest mentioned above, you will
be able to talk to Materia Melder NPCs in city-states and hub cities
and pay them to meld Materia to your gear.
Or, if you have a crafter at level 19 or higher, you can talk to Swynbroes
after completing Forging the Spirit,
to accept and complete the quest
Waking the Spirit. This unlocks Materia Melding.
You will be able to meld Materia into gear if you meet the Materia melding
requirement of that piece of gear. View the gear's information window
and look for "Materia Melding" to see the requirement.
You can also send meld requests to players who are currently a crafter of level 19 or higher (if they have unlocked Materia melding) by right-clicking them and choosing Request Meld, but they can charge gil for it, and you will need to provide the Materia.
Overmelding
You can unlock Overmelding when
you reach level 25 in any class by talking to Mutamix in Central Thanalan
to accept and complete the quest
Melding Materia Muchly. This unlocks
Advanced Materia Melding, which allows you to attach Materia to gear even if all
of its Materia slots are full. However, a given piece of gear can only hold up to
five total Materia (i.e. Pentamelded gear),
and some gear does not support Advanced Materia Melding. The
success rate of Advanced Materia Melding is much lower than that of attaching
Materia to normal slots.