Merge Fields
When you edit a text block, Contact Fields are always available related to both the Recipient and Sender. If you defined the template's Pertains to Page value, Data Fields also display. If you change the Pertains to Page value while you edit a template, you'll need to refresh the data fields. To do this, click away from a text block, then return back to it for refreshed data. 
Note: Data fields used on a main page when you create a template could be unavailable on the related sub-page. Data fields are based on the default field list which varies between pages and sub-pages.