(I changed the terminology in your question to fit Word jargon. What you were describing was AutoText, not a template.)

What you are describing is AutoText. In Word versions up to 2003 a tooltip would appear when you typed the first four unique characters of the AutoText entry name. Word 2007 discontinued doing this as a part of incorporating AutoText into the larger category of "Building Blocks."

The tooltips were returned in Word 2010 but only for AutoText stored in the normal template. (In Word 2013 they were restored for all available templates.) I am assuming that your AutoText is stored in a different template', probably the template for your document.

You can insert the AutoText by typing the unique first characters of the name (at least 4) and then pressing the F3 key. Where appropriate, you could also use the AutoTextList field.

Automated Boilerplate Using Microsoft Word