PC Boxes are fundamental in Pokémon Sword and Shield. Keep Pokémon not in your party and want to use them later. You may have been a little worried about the space available, but there is a way to get more PC Boxes.
This is a simple thing to do. Go to any Pokémon Center and interact with the console to manage your PC Boxes. Go up to it and press A, then select "Checkboxes". You have eight boxes by default. Move a Pokémon from a box and place it in an empty box, and do so until all eight boxes contain at least one Pokemon.
Now, close the menu, then reload again. The number of PC Boxes you have will be doubled. You can do this twice more, to have a maximum of 32 boxes.
It's a simple method of expanding your PC Box space, and you have a better idea of how much space you need to fit all of your Pokémon.
If you need more help with Pokémon Sword and Shield, we have a number of guides you might find useful. From how to use PC Box Link, how to change the nature of a Pokemon, and how to trade Pokémon. If you're looking for some of the rarer Pokémon, we can show you where to find Dreepy and Ditto too.