The Files module has the capability to upload multiple files at the same time. To use this feature, click on the green "+" icon next to Files in the Content dropdown.
You'll be taken to the Files Add screenview. Hover over the Files tab and select Add Multiple Files.
Select the files you'd like to upload. When they've been uploaded, you'll see this:
Return to the Files module listing by clicking File List in the Files dropdown. From here you can view, edit or use your newly added files.