To attach a file swiftly using drag and drop in Outlook:
Automatically Open a Message
An even faster way to create attachments using drag and drop in Outlook is to simply drag the file straight into your Inbox. When you drag a file from File Explorer (or Finder on a Mac) and drop it on the Outlook Inbox, Microsoft Outlook automatically opens a new email message window with the file attached. Then, enter the address, subject line, and content, and send the email.
Can I Attach Multiple Files With Drag and Drop?
The drag-and-drop method for attaching documents works with multiple files. Press and hold the Ctrl key (or Command on a Mac) to select multiple files, then drag the files to your Outlook Inbox or a new message.
Sending Links to Documents on a File-Sharing Service
The drag-and-drop method works only with files on your computer, not with files that reside on a file-sharing service. You can send a link to those files, but Outlook doesn’t download the document and send it as an attachment. When you copy the share link and paste it into your email, the email recipient clicks the link to view the attachment.
