A slate, for spots or shows, most often is simply made using a Character Generator or with an NLE's available titling tools. It will usually have info lines for
Agency or client:
Series Title (if applicable):
Episode or spot Title:
any Program or commercial ID code # (if applicable):
Date (production date, but sometimes also Air Date(s)):
There's no "template" as such. Find a show or spot reel and see how it's done by others.
In most cases the slate is keyed over a countdown clock. If your client wants six seconds, I'll assume they want 8-7-6-5-4-3 plus a 2pop, something that can easily be done by the editor (and saved for future use). Some prefabs are available with Avid and FCP, but it's way too easy to roll your own.
As always, if you're not sure, ask your client.