It's reasonable to assume that any photo sharing app checks EXIF data (and uploads it), including geotags. For some people this is something they want, as some

It's reasonable to assume that any photo sharing app checks EXIF data (and uploads it), including geotags. For some people this is something they want, as some people want the app to be able to show that info or be able to search their library by date/location. If the app does not explicitly say it does not, I'd assume it does. I don't know if facebook/instagram has said if they do or don't.