How to add a supplemental feed in Google Merchant Center

Flexport needs a supplemental product feed in order to turn on Google 2-Day Delivery fast tags

1. Navigate to https://merchants.google.com/mc/products/sources
2. Click "ADD SUPPLEMENTAL FEED" in the "Supplemental Feeds" section
3. Enter "Flexport" for the supplemental feed name, select "Content API", and click "CONTINUE"
   
4. Check all "United States, English" boxes and click "CREATE FEED"
   
5. You will be taken back to the feeds page. Click on the new "Flexport" supplemental feed you just created to see the feed ID. You'll need this to set up Google Shopping 2-Day Delivery fast tags.