In Final Fantasy XIV, crafting is a process by which players can create items using materials obtained from gathering and monster drops. There are eight main crafting classes in the game - Blacksmithing, Armourer, Weaver, Alchemist, Culinarian, Goldsmithing, Leatherworking and Carpenter - each with their own unique recipes and items.
To begin crafting, players must first select a class to level up. They can do this by speaking to the appropriate Guildmaster for that class (for example, the Blacksmithing Guildmaster can be found in Ul'dah). Once they have joined a guild and completed the relevant quests, they will unlock that class's corresponding Crafting Log. This log contains all of the recipes that class can learn, as well as tracking the player's progress towards mastering them.
Players level up their crafting classes by completing certain actions within the Crafting Log. Each time an action is completed (such as synthesis or repair), players will earn experience points towards levelling up that class. As they level up, they will unlock new abilities which will make crafting faster and easier.
Once a player has reached Level 30 in a particular class (the maximum level), they will need to complete a special quest called The Master's Trials in order to receive their Mastercraftsman's Certificate. This certificate allows them to purchase rarer ingredients from vendors, as well as giving them access to high-level guildleves (quests) which offer even better rewards.