at what level will we get it? i noticed armors with materia slot from level 15ish but now im level 22 and still no tutorials explaining it (or did I missed it somehow?).
is there suppose to be a quest for these? I tried to look up at merchant in case they selling it..but nope. can anyone tell me which quest (if there's any) for materias? if not..where do I get it?

thankssss!

The quest for Materia creation is to the east of Horizon in Thanalan.
Should be part of the main quest, where Minfilia introduce you to the Goblin.

There is a few quest to be precise, one taught to you for converting equipment into Materia.
Another require a DoH to around level 16/18 to learn for melding Materia into equipment.
The final one being advanced Materia, i think this one is doing forbidden Materia melding. Melding more materiia to equipment. I am not there yet.

its a lvl20 quest.

Thank you. I'll look it up. Time to progress with my main quest then. so many quests to do..