You can drag and drop files into OneDrive by locating and selecting them in Windows' File Explorer and moving them to the OneDrive folder.

SEE: 20 pro tips to make Windows 10 work the way you want (free PDF) Even though the feature will be a welcome addition, there are some limitations on drag-and-drop file transfers.

Step 1: Drag and drop the PDF you want to convert into Calibre, or click the Add Books icon in the top left-hand corner and select Add Books From A Single Directory.