You can attach files to a message at any time, and these files can come from your computer, Google Drive, or cloud storage like OneDrive/SharePoint and Dropbox. You can attach any type of file, including documents, images, or videos as long as it’s under 1 GB.
The processes for attaching a file from your computer, Google Drive, OneDrive/SharePoint, or Dropbox are a little different, so let’s review each of these methods separately.