Bing Shopping Feed for Shopify has been developed by Simprosys InfoMedia for Shopify stores. 

Bing Shopping Feed Working on Shopify:

• Bing Shopping Feed works as an Add-on on Google Shopping App. 
• In order to avoid double data management for both Bing and Google, we developed this app to work as an add-on because Bing Merchant Center also requires same product data attributes as Google.
• We coded it in such a way that product attribute entries made for Google Shopping Ads can be used for Bing Shopping Ads as well. 
• Syncs all product attributes required to setup feed and segregate the campaigns in Bing Ads Shopping Campaign. 
• Probably the only app, that syncs custom labels. 

So, Google Shopping App must have been installed on your store and you should have submitted all important and required product attributes for each product you want to advertise on. 

Steps of FeedAPIs For Bing Shopping /MS Feed Submission:

1. Select if you want to submit only "One Collection" or "All Products" (Learn more about selection).
2. Review App Pricing based on product counts you get and then submit. 
3. Hit "Generate Feed Button". follow Feed Generation process given here.
4. If your store is having less than 25 Products, Feed URL will be provided in few minutes of feed generation request. 
5. If your store has more products, say 1 million; process may take up to 1 day to get you feed URLs. (We are helpless as Shopify has limits on how many products we can fetch in a minute. Learn more about limits here)
6. Also, you will get feed URL/s in the Eemail to submit them into Bing Merchant Center. 
7. Once feed is submitted, Bing normally takes 24 to 72 hrs to include all the products in the Bing Merchant Center. 
8. But, you can set up the campaign just after submitting the feed.