Crafting missions require you to place certain items (crafters) in your apartment that will allow you to craft items needed to complete mission tasks.
Some of the items may have recipes that require you to request gifts from friends, find ingredients or craft smaller items first. Once you have collected all of the ingredients required, you may then craft the item.
Please note, you are not required to spend Gold in order to complete crafting an item. However you do have the option to use Gold to purchase necessary ingredients or skip or speed up the crafting process.