So, switch to the Google Chrome profile that corresponds to the Google Drive account you want to save files to before using this extension. NOTE: The Save to Google Drive extension saves files to the Google account you are signed in to in Chrome. Related: Everything You Need to Know About Google Chrome's Profile Switcher
The Save to Google Drive extension can also be useful If you’re using Ubuntu Linux, which does not have an official Google Drive client. However, using the Google Drive client uses space on your computer, which isn't ideal if you're low on space.
If you’re using the Google Drive desktop client for Windows or macOS, you can save downloaded files directly to your local Google Drive folder and they will be uploaded to your Google Drive account automatically. Google's Save to Google Drive extension allows you to save downloaded files directly to your Google Drive account, as well as save webpages to Google Drive as images, HTML files, or even Google documents.
