A typical scenario might be that one of your channels wants you to submit a new attribute for your items that you don't already have in your Master data.
This is a common occurrence as Channels are constantly updating their requirements. So the question is how do you add a new attribute?
Adding a new attribute for your items is created by importing a file with at least 2 Column Headings:
The item Id attribute (we recommend using the GTIN as the Id)
Your new attribute
This will create the attribute in your Master data and you can now map it to a new required attribute in a Channel.
As long as you have the product's Id to attach the new attribute to, you can add as many attributes as you wish.
Tip
You can add/create new attributes in bulk when importing by selecting the "Create new attributes for all unmapped" option as shown below.