Kathy, you can’t make link previews in the letter while you are writing it (I am pretty sure.) You can only paste the URL. But when Medium sends the letter, it also posts it on Medium to your account. Then you CAN open the published letter on Medium and turn the URLs into link previews the usual way.

Try placing the cursor at the end of the URL and hit enter or return. If that doesn’t work, you can cut the link, paste it again and then hit return. It should change then.

It would be nice if we could do it in the letter, but I can’t find a way to do it.