When you download a game from the Epic Games Store that contains downloadable content (DLC) all of the content is usually downloaded during the initial download. However, some games may require additional content to download.
To manage additional DLC content, do the following :
Note: Not all games that have DLC will have a Manage DLC option because the content is downloaded with the main game.
Example: Football Manager 2022's in-game editor
If you try to download the DLC and don't have enough disc space, you'll receive an error message letting you know how much space you need to free up to download the DLC.
For steps on how to free up hard drive space, see this article.