Share and collaborate with Outlook on the web
Share a file in a message
Select New > Email message.
Choose which files to share and select Next.
Select Share as a OneDrive link.
To share a file on your C: drive:
Select Upload and share as a OneDrive link to upload the file to OneDrive and share the link.
Use @mentions to get someone's attention
In the body of the email message or calendar invitation:
Type the @ symbol and the first few letters of a contact's first or last name.
Choose a contact from the list.
This adds the contact to the To line of the email message or meeting invitation.
Note: @mentions are only available for Exchange Server 2016, Exchange Online, or Outlook.com users.