Hi Lisa 

Thanks for posting in the Lucid community! There is not a limit to the number of documents that a team folder / sub-team folder can hold. However every account type has a different amount of storage. You can find the details for each account level in this help center article.

Also you can check how much of your storage is being used (and what it is being used by) in your Account Settings at the bottom of the left panel. If you hover over each of the colored sections you can see what that portion of the storage represents.

Thanks again for posting in the community!