The command "Stand" teaches your dog to stand back up and to hold the standing position. This command can be especially useful for 'stacking' dogs, a term used in the show world for their dog to pose and stand still for the judge, but can also be used for everyday training.
A few of it's uses include being able to 'Stand' on the grooming table for a haircut, having your dog 'Stand' to wash them off or check for injury, or even having them 'Stand' as still as possible for dogs with more wiggly bottoms!
To teach this command, start your dog in a 'Sit' or 'Down'. Have something interesting in your hand, such as a tasty treat! Face your dog and put the treat in front of your dog's nose. Gently move your hand in a straight line towards you. Your dog should follow your hand and break the 'Sit' or 'Down' position to stand up. As soon as they do, say YES! and give them the treat. Try to have your dog take as little steps as possible, aim for having them simply go into a standing position.
Tips and training like this can broaden your dogs mind and keep them stimulated!