Edit icons for Office files in Gmail desktop attachments

In Gmail, with a single click on the pencil icon in the attachment card, you can now convert any Office files sent as attachments to Docs, Sheets, or Slides. You can then start editing and enjoying the full benefits of a single document to keep track of, access from anywhere, and full revision history.

Release track:

Rapid release, with Scheduled release coming in two weeks

For more information:
Help Center
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Reference by www.google.com