From the software
Send a link of your design by clicking Share in the upper right corner of the editor, then Share Link.
From your homepage
From Home or All My Designs, hover over the design you would like to share. Click the three dots as shown below. Tools will appear including Share, then click Share Link.
In either case, click copy to get the share link.
Syncing your changes from the editor
After you've updated your design, click Share in the upper right corner of the editor, then Share Link (a needs sync message will appear if necessary). Click sync changes to update the link with your latest design edits.
Syncing your changes from your homepage
From Home or All My Designs, hover over the design you need to sync. Click the three dot icon, then Share to update the share link.