Use the Edit (old UI) or Edit Online (New UI) option to perform secure collaborative edits on your documents. Collaborative edits can be performed on all major file types such as documents, spreadsheet, and so on. Edits are done by using the Browser, and no Native application is required.
Navigate to the file that you want to perform collaborative edit.
Click the drop-down arrow next to the file that you want to view, then click Edit (old UI) or Edit Online (New UI). This opens a browser to edit the file.