Introduction is the stage of meeting the in-laws, for a couple to be married traditionally the introduction stage is important.
The groom's family introduces themselves to the bride's family, and asks for their daughter's hand in marriage to their son.
The introduction takes place at the bride's house, and her family is responsible for the preparations and costs, but if the groom's family is able to, they can suggest helping out with some of the costs and/or the food.