To upload files/folders using the web application, you can use the Drag and Drop or File Upload method. To upload files using a mobile or desktop client, see the documentation for the app.
Drag and Drop
You can drag and drop files/folders directly into the Datto Drive page:
Datto Drive also supports batch uploads of files. You can group-select, and then drag and drop multiple files from your environment directly into the file manager GUI.
Be aware that any files/folders larger than 4GB will need to be uploaded via the desktop client.
You can also use the File upload menu item.