Hi,
You can use a Seller Details Profile for most of the common info, like payment, shipping, terms, etc. That adds the info with the approprate predefined headers you see in Templates. You can also create more than one to cover all your cases.
For anything else, you can create a custom template and add your own special sections with text. And, you can use the Seller Details tags to add that info too.
Lots of flexibility with the Template tag system.
See the Sticky thread on the Template section of the Forum for a quick list of the Template Tags.
Danno