In Outlook on the web, when you write an email and add a URL, or when you receive an email with URL inside it, you get a rich preview that includes a link title, thumbnail, and description of the link. This is called Link preview.
Instead of this: http://www.microsoft.com
With Link preview, you get this:
Note: Link preview is turned on automatically. If you are not seeing a link with a thumbnail, title, and description like the one shown above, you will want to turn it on. If that doesn't work, see your IT administrator.Add a Link preview
In a new email, type the URL of the site you want to provide a Link preview for. For example: http://microsoft.com
Link preview will automatically go to the destination URL and provide the site's name, description, and thumbnail (if there is one available) in the email.
Add an indented paragraph under a numbered step by placing cursor before the /para tag, then press Enter.
Note: To open or follow a Link preview, simply click it like any other hyperlink.
Turn Link preview off
Link preview is turned on automatically, however you can turn it off.
On the Navigation bar, in the upper right corner, click Settings .
In the Options pane, under Mail > Layout, click Link preview.
Under Link preview, uncheck the Preview links in email box to turn it off.
Note: Check the Preview links in email box to turn it back on.