In Online Office, you can open files from your GMX
Cloud or upload locally stored files from your computer.
Please note that only the following file formats are supported: .doc, .docx, .odt, .rtf, .txt, .ppt, .pptx, .odp, .xls, .xslx,
You can upload locally stored files from your computer to view and edit them in Online Office.
You can open files that are saved in your Cloud in Online Office to view and edit them.