Here is a list of all supported file formats.
Creating a New File
Opening an existing file
Selecting File -> Open from brings up the following sub-menu:
You can choose to open a file from any of the five storage options, or, if a file is available from a web page, you can open it via that web page's URL.
Note that if you are opening from any of the remote storage options (Google Drive, Dropbox, or OnDrive) you may need to provide authentication if you are not logged in. Details on this are provided in the individual sections for each storage option.
Once any authentication has been completed, the file picker associated with storage option will be brought up. For this example, we will be starting in Dropbox, and opening a file from local storage in the browser.
Here we can see that only one file is currently being stored in the browser. Clicking this file will cause the file to open in a new tab.
Because we have opened the file from local browser storage, Browser is the selected storage option for that file. If we save the file using File -> Save, it will be saved in the Browser, overwriting the previous version. To save it in Dropbox, or any other storage option, use File -> Save as and change to the desired storage option.