I haven't uploaded any to OneDrive yet and haven't spent the time to completely understand the following but it may (or may not) help. See the entire article, including the excerpt below, at iOS 11's new image format might pose problems for PC users - The Verge
Google Photos and Dropbox both support HEIC within their apps, but Microsoft has been to slow to support the new format. Still, the latest version of OneDrive will automatically convert HEIC photos to JPEG before uploading them to the service. This means that although HEIC isn’t natively supported on Windows 10, you won't need a dedicated photo app or a method to convert files in order to view your iPhone photos on a PC. You'll be able to view them on OneDrive mobile apps, OneDrive.com, and in Windows 10. You can also turn off the feature by going to settings > advanced > upload most compatible feature.