We haven't seen this documented, but the Communication Wizard supports a cool feature to specify what your communication's email preview text should be. The preview text is what email clients display when listing your email in the inbox (at least in Outlook):


By default, Outlook will display the first text it finds in the body of an email as the preview text. So, unless you specifically control that, the first text may not be the best preview text to use. You can control that though, by adding an invisible HTML element as the first content in your communication templates. Here's a sample:

<span id="preheader-text" class="preheader" display: none !important; font-size: 1px; 
line-height: 1px; max-height: 0px; max-width: 0px; mso-hide: all !important; opacity: 0; 
overflow: hidden; visibility: hidden;"></span>

It's important that this is the first HTML after the opening <body> tag:


Notice that the element doesn't have any actual text contents. That's OK. As long as the element has the ID of "preheader-text", the Communication Wizard will display an additional entry field to specify what the preview text should be for each communication that is being sent:


The communication wizard will look to see if there is an HTML element in the selected template with a "preheader-text" ID. If there is, it displays the "Email Preview" entry field and then adds that value to that element when creating the email. Because that element is the first item in your email (even though it's hidden), Outlook will display that as the preview text.