each product can have its information changed slightly to cover differences across different marketplaces. Open any product, and click on marketplaces at the top, and you should be greeted with something like this
here you can adjust the meta tag info on your standard websites, and if you have added the other marketplaces to your account those options should be here as well
with amazon looking like this
ebay looking like this
and Reverb looking like this
Marketplaces makes it easy to keep each items information set up correctly, or changed as needed for separate platforms.