Changing something in Google Drive on the web
Owner / editor
Your changes sync to every collaborator’s Google Drive on the web, Google Drive folder, and Google Drive mobile app when you update online copies in your Google Drive on the web.
If something is included in multiple folders, any changes to the item will be reflected in all of the folders.
Commenter / viewer
As a commenter, you can't edit online copies.
Changing something in your Google Drive folder
Owner / editor
Your changes sync to every collaborator’s Google Drive on the web, Google Drive folder, and Google Drive mobile app when you update local copies.
When a local copy is modified, a new version of that file will sync to every collaborator’s Google Drive on the web. If two people make changes to the same file, both versions will be available online in the file’s revision history. Only the latest version of a file will be available every collaborator’s Google Drive folder.
Commenter / viewer
As a commenter, you can't edit local copies. The Google Drive folder on your computer will store the most updated version of a file.