Pokemon Camp is a feature in Pokemon Sword and Shield accessible through the X menu that allows you to play, cook, and meet other trainer's Pokemon. The feature is given to you right before entering the Wild Area, by the player character's mom.
When cooking with your Pokemon, you can use different berries and food ingredients to make curry. There are 151 different kinds of curry you can make, and completing larger parts of the curry Dex can give you more Pokemon Camp rewards, (ingredients, special balls to play with, etc.)
A maximum of four people can be in the same Pokemon Camp.
Very, very rarely when in Pokemon Camp, a wild Pokemon can come into your Camp and join your party.