Have you ever had a corgi before (if not, here’s an excellent source to familiarize yourself with the breed)? Have you ever had a dog before? Are you planning on getting an adult corgi or a puppy? Are you going to adopt from a local shelter/rescue? Are there responsible breeders* in your area (https://www.akc.org/press_center/facts_stats.cfm?page=responsible_breeder)? These are all things to consider before you bring a corgi home.
If you’re just starting out with dogs or bringing a puppy home, it’s best to start with ONE. This is to help you build a bond with your dog, make training easier (trust me, corgis are a handful) and when you have two puppies of same or similar ages they will bond more to each other over their person. You want to establish a strong relationship with your dog to start, and if you have properly trained your corgi it will make bringing a second dog home easier. Once you’re past house breaking, preliminary training, and spay/neuter you’re much better equipped to bring another corgi into your home.
Corgis thrive in single dog homes and in pairs (or more! There’s no such thing as too many corgis!) and can be quite independent animals. But they are highly intelligent working dogs and must be treated as such. They need plenty of physical and mental stimulation and cannot be left to their own devices unattended. Even with a playmate, your corgi will need you for exercise and obedience and guidance. If you think one corgi can get into a lot of trouble (or pick up destructive behaviors) left unattended, imagine what could happen with two.
Corgis are a lot of hard work, and they take a lot of effort; but trust me, they are worth it!
*Pro-Tip: A responsible breeder would never let two pups from the same litter go to the same home, or two pups go to a first time dog owner at the same time. If the breeder you’re talking to suggests that, find another breeder or look to rescue/adopt.