Just documents. Laserfiche cannot import a "folder" in the traditional sense. However, Import Agent can import documents in subfolders of a monitored directory, and you can use portions of the original path to construct the destination path in Laserfiche.

For example, if I have a file in a network share with path:

\\share\ImportAgentMonitoredCasesFolder\Case123\Reports\JuneMonthlyReport.pdf

And I have my Import Agent profile configured to import all docs in the monitored folder and its subfolders, I can easily use the path tokens to construct a similar repo path and import the doc to:

MyRepository\Cases\Case123\Reports\JuneMonthlyReport.pdf

Etc.