Item Templates are stored in the Create Items window:

Let's examine what Item Templates are:
An Item Template is a record which holds the default data for all or
a group of items you typically list.
If you, for example, sell postcards, antique jewelry and autographed
baseballs, you may very well want to create 3 Item Templates, as each
item within each of those groups will share much of the same information.
I have 2 main Item Templates I generally use: one for my own items I list,
as the are usually the same size and I start them at the same price -
and - another for creating item records for my main consignment client,
as I don't want to have to enter consignment info for each of her items
I list.
I will use a fictitious seller, Frank, as the seller of postcards, antique
jewelry & autographed baseballs as a sample for this workshop. Frank
will want 3 separate Item Templates, 1 for each of his category of products.
For example, he lists the majority of his postcards in his eBay store,
sells most at $14.99, ships them via first class mail at $1.50, usually
lists in the National Parks postcard category, uses his store category
"Collectibles - Paper", uses his Postcards Ad Template and uses
a gallery photo for each. He will also set his Shipping To/From and Payment
presets as appropriate. Thus, he creates an Item Template which has those
fields filled in:

eBay Certified Stores Designer. Click to see
my ME page for links to Blackthorne Pro workshops & FREE templates. 
eBay Certified Stores Designer. See my ME page for links to Blackthorne Pro help & FREE templates.
